Chuyên đề pt,bpt mũ –lôgarits GV: Lơng Thị Lan Phơng BÀI TẬP VỀ PHƯƠNG TRèNH MŨ Bài1: Giải cỏc phương trỡnh sau: 1... Chuyên đề pt,bpt mũ –lôgarits GV: Lơng Thị Lan Phơng9... Chuyên đề p
Trang 1Chuyên đề pt,bpt mũ –lôgarits GV: Lơng Thị Lan Phơng
BÀI TẬP VỀ PHƯƠNG TRèNH MŨ
Bài1: Giải cỏc phương trỡnh sau:
1 9x+1 = 27 2x+2
2 3 2x+ 5 = 3x+ 2 + 2
3 2x− 1 + 2x− 2 + 2x− 3 = 448
4 3x− 1 2x2 = 8 4x− 2
5 2x 5x = 0 , 2 ( 10x−1 ) 5
6 ( 2 + 3 ) 2x+ 3 = 2 − 3
7 2x2− 3x− 2 =41
8 2 3x+ 1 − 6 3x− 1 − 3x = 9
9 2x+ 1 5x = 200
10 0 , 125 4 2x− 3 = ( 4 2 )x
11.3x+1+ 18 3 −x = 29
12 27x+ 12x = 2 8x
13 3 4x = 4 3x
14 3 .8x+ 1 =36
x
x
15 x6 5−logx5 = 5−5
16 6x+ 6x+1 = 2x+ 2x+1 + 2x+2
1
9 6
4
1
= + −
−
18 2 sin2x + 4 2 cos2x = 6
1 2 cos 1 2
cos
2
17 7
5
128 25 0
+
−
+
x x
x
21 4x − 3x−0 , 5 = 3x+0 , 5 − 2 2x−1
22 5x−1 = 10x 2−x 5x+1
23 3 4x+ 8 − 4 3 2x+ 5 + 28 = 2 log2 2
Bài 2: Giải phương trỡnh sau:
1.(3 − 2 2)3x = 3 + 2 2
2 5x+ 1 + 6 5x − 3 5x− 1 = 52
3 3x+1 + 3x+2 + 3x+3 = 9 5x + 5x+1 + 5x+2
4 3x 2x+1 = 72
x
2 1
125
25
1
=
6 ( 0 , 5 ) 2 + 3x = ( 2 ) −x
7 4x+ 1 − 6 2x+ 1 + 8 = 0
8 3 1 +x + 3 1 −x = 10
9 3 25x + 2 49x = 5 35x
10 32x+4+ 45 6x − 9 22x+2 = 0
11 8x+ 1 + 8 ( 0 , 5 ) 3x + 3 2x+ 3 = 125 − 24 ( 0 , 5 )x
12 ( 6 + 35) (x+ 6 − 35)x= 12
13 5 7x = 7 5x
14 5 .8 x−1 =500
x x
15 5 3 − log 5x = 25x
16 x−6 3−logx3 = 3−5
17 9xlog9x =x2
18 x4 5 3 = 5 logx5
19 2x2−4 = 3x−2
20 4log0 , 5(sin2x+5sinx.cosx+2) =91
21* 3x = 5 − 2x
5
− +
−
=
23* 6x+ 8x= 10x
24* ( 5 + 2 6) (x + 5 − 2 6)x = 10x
25*.( 2 − 3) (x+ 2 + 3)x= 2x
6
1 2
1 2 3
1
−
− +
x x x
x x
27.3 2x− 1 + 3x− 1 ( 3x− 7 ) −x+ 2 = 0
28 25 5 −x − 2 5 5 −x(x− 2 ) + 3 − 2x= 0
29* xlog29 = x2 3 log2x − xlog23
30* 3 4 5 2
x
31 2 cos2x + 4 2 sin2x = 6
32
0 5
15
1
8 log sin cos 1
cos 2 sin
+
x x x
x
Bài 3: Giải cỏc phương trỡnh sau:
1.5x2 − 3x2+1 = 2(5x2−1 − 3x2−2) ĐS:
3
;
x
5 10
10
8 125 , 0
+
−
+
x x
x
3.3x−1 = 18 2x 2−2x 3x+1
17 7
5 2187 9
1
+
−
+
x x
x
5 2x−1 − 3x = 3x−1 − 2x+2
6 7 3x + 9 5 2x= 5 2x + 9 7 3x
x x x
1 5 1
1 5
2 4
2
1
1 2
3
3 2 2
9x − x+ = x+ − x−
Trang 2Chuyên đề pt,bpt mũ –lôgarits GV: Lơng Thị Lan Phơng
1 1
3
3 10 3
+
−
−
−
=
x x
x
10 2x 3x+1 = ( 3 )x+2
11 ( ) 2 2 24 9 2 12
5
3 5
.
6
,
x
x
x x
x
1 2 1 4 1
3 2 ) ( 4 ) 2
(
)
2
−
−
2
1 4 6 9
.
3
1
4
.
3 x + x+ = x+ − x+
14 2x + 2x−1 + 2x−2 = 3x + 3x−2 − 3x−1
15 x x =x 2x− 3
16 (x2 − 5x+ 4)x2−4= 1
17 (x+ 4 )x2− 5x+ 6 = 1
18 x3 2x = ( x)x
x x
− +
+
=
+
1 2
1 5 2
1
2 1
2
20.(x2 − 2x+ 2 ) 9 −x2 = 3 x2 − 2x+ 2
21 (x2 −x + 1 ) 4 −x2 = x2 −x + 1
Bài4: Giải cỏc phương trỡnh sau:
1 3 2x2+6x−9 + 4 15x2+3x−5 = 3 5 2x2+6x−9
2 3x+ 2 + 9x+ 1 = 4
3.4x+ 3 + 2x+ 7 − 17 = 0
4 5 1 +x2 − 5 1 −x2 = 24
5 5 x − 5 3 − x − 20 = 0
6 4 x − 4 1 + x = 3 2x+ x
1 1
1
25 35
8 125x + 50x = 2 3x+1
9 2.49 2 9.14 2 7.4 2 0
= +
x
10 25 3.101 21 2 0
2
1
1
=
−
+
x x x
11 4x+ x2− 2 − 5 2x− 1 + x2− 2 = 0
12 4x− x2 − 5 −12.2x 1− x2−5 +8=0
13 3.2 8.2 2 4 0
1 1
1
= +
+
x
x
14 82 +23x+3 −20=0
x
x
15.3 2x+ 4 + 45 6x − 9 2 2x+ 2 = 0
16 22x 9x − 2 63x−1 + 42x−1 34x−2 = 0
17 8x + 18x = 2 27x
6
1 3 5 2
−
=
x
1 1
1
9 6
4
.
20 4 =92 +7
x x
21 22x − 3 2x+2+ 32 = 0
22 5 3x + 9 5x + 27 ( 5 − 3x + 5 −x) = 64
23 23x − 6 2x − 23(1−x) + 12 2 −x = 1
24 ( 2 + 3) (x+ 2 − 3)x= 4
25 ( 4 + 15 )x + ( 4 − 15 )x = 62
26 ( 2 + 3 )x + ( 7 + 4 3 )( 2 − 3 )x = 4 ( 2 + 3 )
27 ( 7 + 4 3 )x − 3 ( 2 − 3 )x = − 2
28 ( 3 + 5 )x + ( 3 − 5 )x= 7 2x
29 3 ( 1 + 5 )x − ( 5 − 1 )x = 2x+1
30 ( 7 + 4 3)cosx+( 7 − 4 3)sinx = 4
) 1 5 ( 3 2
) 5 1 ( + x−x + 1 +x−x = − x−x
32 3 25x + ( 3x− 10 ) 5x− 2 + 3 −x= 0
33 9x + 2 (x− 2 ) 3x + 2x− 5 = 0
34 x2 − ( 3 − 2x)x+ 2 ( 1 − 2x) = 0
Bài 5:Giải cỏc phương trỡnh sau:
1 2x+ 1 + 3x= 6x + 2
2 15x − 3 5x + 3x = 3
3 2x+ 1 + 3 2 2x = 6 + 2 3x
4 4x2 +x 3x+ 3x+ 1 = 2x2 3x+ 2x+ 6
5 2 2x2−5x+2 + 2 4x2−8x+3 = 1 + 2 6x2−13x+5
6 2x2−3x+3 + 2x−1 = 2 + 2 (x−1 ) 2
7 3 4x−3 + 3x−2 = 9 + 3 5x−7
8 5 3 − 2x2 + 5x2 +x− 1 = 5 + 5 1 +x− 2x2
9.x2 2x + 6x+ 12 = 6x2 +x 2x + 2x+1
10.x3 3x + 27x=x 3x+ 1 + 9x3
11.x2 2x+1 + 2x−3+2 =x2 2x−3+4 + 2x−1
12.( )7 x+1+ 7x2− 2 = 7x2+x− 4 + 7
Bài 6: Giải cỏc phương trỡnh sau.
1.5 .8 x−1 =500
x x
2.3x2− 4 = 3 25 125x
x
+
(
3 36 3 8
4 2x2− 2x 3x = 1 , 5
5 4x 6x = 2 9 2x
6 3 .8x+ 1 =36
x x
7 5 .2 1 4
3
x x
8 4tan4 = 1600 2
x
x
Trang 3Chuyên đề pt,bpt mũ –lôgarits GV: Lơng Thị Lan Phơng
9 4 xtan x = 100
10 7 log252( 5x) − 1 = xlog57
Bài 7: Giải cỏc phương trỡnh sau:
x
2
1
3 2 + =
2 ( 4 + 15 )x + ( 4 − 15 )x = ( 2 2 )x
3 2010 sin2x − 2010 cos2x = cos 2x
x
4
7
9 2 + =
5 3 4 5 2
x
6 3x+ 4x+ 5x+ 14 = 8x
7.82 −32 −2x =39
x
x
8 2x+ 3x + 6x = ( 0 , 7 )x+1
9 15 2x + 4 7x = 23 , 5 10x − 6 5x − 4 3x
10 2 5 29 2
x x
11 ( 2 − 3 )x+ ( 2 + 3 )x= 4x
12 ( 3 − 2 )x+ ( 3 + 2 )x= ( 5 )x
13 x2 − ( 3 − 2x)x+ 2 ( 1 − 2x) = 0
14 x 2x =x( 3 −x) + 2 ( 2x − 1 )
15 3 25x− 2 − ( 3x− 10 ) 5x− 2 + 3 −x= 0
16.9x + 2 (x− 2 ) 3x + 2x− 5 = 0
17 2x+ 3x+ 5x = 10x
18 ( 3 + 5 ) 2x + 7 ( 3 − 5 ) 2x = 2 2x+3
19.2x− 1 − 2x2−x = (x− 1 ) 2
20 π sin x = cosx
**************************
BẤT PHƯƠNG TRèNH MŨ
Bài 8: Giải cỏc bất phương trỡnh sau:
1.2 3 − 6x > 1
2 2x+2 − 2x+3 − 2x+4 > 5x+1 − 5x+2
1
32
.
4
1
−
x x
x
4 9x < 2 3x+ 3
5.5 2x+ 1 > 5x + 4
6 2x+ 2 −x+ 1 − 3 < 0
2
1
( x2− 5x+ 4 >
8 6 2x+3 < 2x+7 3 3x−1
9 9x < 3x+ 1 + 4
10 3x − 3 −x+ 2 + 8 > 0
11 xlog3x+4 < 243
12 15 2x+3 > 5 3x+1 3x+5
Bài 9: Giải cỏc bất phương trỡnh sau:
1.( 4x2 + 2x+ 1 )x2−x > 1
2 2x + 2x+1 ≤ 3x + 3x−1
1
1 ( 5 2 ) )
2 5
−
x x
4 ( 2 + 1 ) +1 ≥ ( 2 − 1 )x− 1
x x
1 1
3
3 10 3
+
−
−
−
<
x x
x
3
1
3 2
−
−
≥
x x x
x
2 2
1
3
−
−
+
+
−
>
+
x x
x
x x x
x
8 − 12x2−7x+3 < 1
x
9 3x2+2 + 3x2 ≤ 2 5x2+1
3
1 3
1
3 72 >
11 2log 3x2.5log 3x <400
12 (x+ 3 )x2− 5x+ 6 > 1
13 (x2 − 8x+ 16)x−6< 1
14 3 logx+ 2 < 3 logx2+ 5 − 2
15 log .log 1
1
<
x
x x
16 x2 logx ≥ 10x
9 6
8x ≥ x−
18 x −x + −x
<
2
1 2
19 2 2x− 1 + 2 2x− 3 − 2 2x− 5 > 2 7 −x + 2 5 −x − 2 3 −x
20 2 49x2 − 9 14x2 + 7 4x2 ≥ 0
21.25 2x−x2 + 1 + 9 2x−x2 + 1 ≥ 34 15 2x−x2
22 5 2x−10−3 x−2 − 4 5x−5 < 5 1+3 x−2
23 4x2−1 + 2 2x2−6 > 52 + 4x2−2
24 3x+1−22x+1−122x <0
25
3
2 4 5 12 5
5 7 4 1
+
−
−
x
x
26 8 3 x+4x + 91+4x ≥ 9 x
27 3 2x − 8 3x+ x+ 4 − 9 9 x+ 4 > 0
1 2
1 2
2 1
≤
−
+
−
−
x
x x
29 9x − 3x + 2 > 3x− 9
Trang 4Chuyên đề pt,bpt mũ –lôgarits GV: Lơng Thị Lan Phơng
30 13x− 5 ≤ 2 ( 13x + 12 ) − 13x + 5
31 5x + 3 ≥ 2 ( 5x+ 4 ) − 5x− 3
32 ( 26 + 15 3 )x + 2 ( 7 + 4 3 )x − 2 ( 2 − 3 )x < 1
Bài 10: Giải cỏc bất phương trỡnh sau
1.4x2 +x +21 −x2 ≥2(x+ 1 ) 2 +1
2 4x2 +x 3 x + 3 1 + x≤ 2x2 3 x + 2x+ 6
3 4x+ 8 2 −x2 > 4 + (x2 −x) 2x+x 2x+ 1 2 −x2
4 2 − 5x− 3x2 + 2x> 2x3x 2 − 5x− 3x2 + 4x2 3x
5 2x+1+ 3x+1< 6x − 1
6
10
29 5
2
2
5 1 >
+
2
4
2
3
3 2
≥
−
−
+
−
x
3
2
3
.
5
2
1
1
<
−
−
+
+
x
x
x
x
PHƯƠNG TRèNH LễGARIT
Bài 11: Giải cỏc phương trỡnh sau:
1.log 1 log ( 2 1 )
2 1
2 = x −x−
x
2.log4(x+ 12 ) logx2 = 1
log 2
4 2
log
6
2 2
= +
x x
4 log3( 3x + 8 ) = 2 +x
5.log2x(x− 1 ) = 1
6 log2x+ log2(x− 1 ) = 1
7 log log log 3
2 1 4
2 x+ x=
8 log 3 x log3 x log9 x= 8
9 log 2x3 − 20 log x+ 1 = 0
10 loglog 2x x loglog 48x x
16
8 4
11.log9x27 − log3x3 + log9243 = 0
12 3 2 − log 3x = 81x
13 log2x= 3 −x
14 log2( 3 −x) + log2( 1 −x) = 3
2 ( 9 2 ) 10
16 log ( 3 1 ) log ( 3 1 3 ) 12
3
3 x − x+ − =
17 logx−14 = 1 + log2(x− 1 )
2
2 ( ) log log
=
+
2
1 log 2
1
3 3
20.4 lnx+ 1 − 6 lnx − 2 3 lnx2+ 2 = 0
21 3 log2x − log28x+ 1 = 0
8 log ) 4 (
2
23.log (log 2 3 log0,5 5 ) 2
5 , 0
24.log2( 4 3x − 6 ) − log2( 9x − 6 ) = 1
2
1 ) 1 2 log(
2
1
3
1 ) 2 ( log 6
1
8 1
2 x− − = x−
Bài 12: Giải cỏc phương trỡnh sau
1 log3x(x+ 2 ) = 1
2 log3x+ log3(x+ 2 ) = 1
3 log ( 2 3 ) log2( 6 10 ) 1 0
2 x − − x− + =
4 log ( 2x+ 1 − 5 ) =x
2
5 2 log 2x= log(x2 + 75 )
2
1 ) 10 log(x+ + x2 = −
7 log22(x− 1 )2+ log2(x− 1 )3= 7
8 log4x8 − log2x2 + log9243 = 0
9 3 log3x− log33x− 1 = 0
10 4 log9x+ logx3 = 3
6
7 log 3 logx − 4x+ =
81
27 9
3
log 1
log 1 log 1
log 1
+
+
= +
+
13 log ( 2 5 ) log 4 3
5 2
2
2 x − + x2− =
14.log9(log3x) + log3(log9x) = 3 = log34
15 log2 x log4 x log8x log16x =32
2
4
5 log 2 6 log log
17 5 3 − log 5x = 25x
18 x−6 3−logx3 = 3−5
19 4log0 , 5(sin2x+5sinx.cosx+2) =91
20 log 5 23
2
1 x= x−
21 x log(x 2x 1 ) logx
2
1 ) 1
Trang 5Chuyên đề pt,bpt mũ –lôgarits GV: Lơng Thị Lan Phơng
22 log ( 3 2 ) log 2 3 1
3
10 log )
1 3
24 x+ log5( 125 − 5x) = 25
25 2 log3cotx= log2cosx
26 log2x− log4(x− 3 ) = 2
x
x x
2 log log
log
.
log
125 5
25
) 3 ( log
) 4 ( log 2 ) 3
(
log
1
2 4 1
6
= +
− +
x x
29 7 logx +xlog 7 = 98
Bài 13: Giải cỏc phương trỡnh sau:
1.log ( 3 2 2 1 ) 21
x
2 log ( 2 4 7 ) 2
2 x − x+ =
3 logx( 2x2 − 3x− 4 ) = 2
4 logx( 2x2 − 4x+ 3 ) = 2
3 2 2 8
2+ + + + x − x =
x x x
x
6 log ( 9 16 ) 2 log (31 4 2)
2
4 4
3 − x2 − x = + − x
7 log ( 4 1 ) log ( 2 3 6 )
2
2 x + =x+ x+ −
8
) 1 (
log ) 1 (
log
) 1 (
log ) 1 (
log
2 4 2 2
4
2
2 2
2
2
+
− +
+ +
=
= +
− +
+ +
x x x
x
x x x
x
9.log (2 54) log ( 3) 2log9( 4)
3 1
2
10 2log2x+log 2 x+log21x=9
11 log 3log log 2
2 1 2
2
2x+ x+ x=
12 log 2 log5 5 1
x
2 1 2 2 log
14 3xlog3x+ 2 = 4x+ log27x
15 log 5 log 5
1
1 3
5
+
−
x x
16
2 log 3 log 2 ) 6 log(
) 1 3 3 log(
3
1 36 log
+ +
+
=
= + + + +
−
x
x x x x
) 4 5
log(
log
−
x
x
3 1 3
3x+ x+ x=
4 2 log ) 2 1 ( log
2 1
) 1 log(
1
2 )
1 ( log 1
) 1 log(
1
− +
+
− +
−
+
x x
x
21
x x
x x x
x x x
2
) 3 2 5 ( log 3 2 5 log 2
2 6 1
2 6 2
+
=
=
−
−
−
−
−
22 4 − logx= 3 logx
23 x(log 5 − 1 ) = log( 2x+1)-log6
24 (log log 2 ) log( 1 2 ) log 6 2
1
= +
+
x
25 log ( 2) log 2 1 0
3 1
3 x− + x− =
26
2
11 log
log log2x+ 4x+ 8x=
27 log ( 2) 2 6log 3 5
8 1
2 x− = + x−
28 log ( 4 ) log ( 2 4 )
6 4
2
2
3+ x − = − x −
x x
x
Bài 14: Giải cỏc phương trỡnh sau:
1
) 1 (
log
) 1 (
log ).
1 (
log
2 6
2 2
2 2
−
−
=
=
− +
−
−
x x
x x x
x
2.log2x+ log3x= 1
3 log5x+ log3x= log 15
6
7 log 2 logx − 4x+ =
5
4 log 1 log log 2
x x
6 log 2 14log16 3 40log4 0
2
= +
x
7 log4(log2x) + log2(log4x) = 2
8 log2(log3x) = log3(log2 x)
Bài 15: Giải cỏc phương trỡnh sau:
1 log2( x − 1 ) = log5x
3 2
2 3 4
8+ x − x− = + x − x−
3 log (x2 x 8 ) log33x
4 log3( 5 + 3 x) = log2( x − 4 )
2 ( 1 ) log
Bài 16: Giải cỏc phương trỡnh sau:
Trang 6Chuyên đề pt,bpt mũ –lôgarits GV: Lơng Thị Lan Phơng
1.(x− 2 )[log2(x− 3 ) + log3(x− 2 )]=x− 1
2.log ( 1 5 5 ) log ( 2 5 7 ) 2
3
2
2 + x − x+ + x − x+ =
********************************
BẤT PHƯƠNG TRèNH LễGARIT
Bài 16: Giải cỏc bất phương trỡnh sau:
1 log5( 3x− 1 ) < 1
2 log31(5x−1)>0
5
,
0 x − x+ ≥ −
4 log31−2 ≤ 0
x
x
5 log 2 log0,5 2 0
5
,
0 x+ x− ≤
6 log ( 2 2 ) log0,1( 3 )
1
,
0 x +x− > x+
7 log ( 2 6 5) 2log3(2 ) 0
3
1 x − x+ + −x ≥
8 11 loglog 21
2
4 ≤
−
−
x
x
9 log (6 1 36 ) 2
5
1 x+ − x ≥
10 log ( 2 6 18) 2log5( 4) 0
5
1 x − x+ + x− <
11 log21(5x+1)> −5
1
3
1
−
+
x
x
13 log ( 2 1 ) log0,8( 2 5 )
8
,
0 x +x+ > x+
1
2 1 (log
3
+
+
x x
15 xlog3x+4< 243
16 log 2 log24 4 0
2x+ x− ≥
17 log 3 log 3 0
3
<
− x
x
18 log2(x+ 4 )(x+ 2 ) ≤ 6
1
1 3 log
log2 4 2 >
+
− +
x
x x
20
−
<
−
4
1 log 1 2
1
log
3
1 3
1
x x
21 3 logx4 + 2 log4x4 + 3 log16x4 ≤ 0
1
1 (log log ) 1
1 (log
log
3
1 4 1 3
+
<
+
−
x
x x
x
23.log4 x− 3 < 1
24 log2x+ log3x< 1 + log3x log2x
2 log
2 log log
≠
>
>
−
+
x
x
a a
Bài 17: Giải cỏc bất phương trỡnh sau:
1 1
3 2 log
1
3 1 2
3
1 x − x+ > x+
2.log2x64 + logx216 ≥ 3
3 log ( 1 1) 1 loglog( 2( 3)1)
2
2 2
+
>
+ +
x x
x
4 log ( 1) log5(2 ) 5
5 logx( 3 − 2x) > 1
2 8
3 log > −
− x
x
7 log 2 2 3 ≤21
−
x
x
x
8 log (2 ) 8log (2 ) 5
4 1
2
2 −x − −x ≥
9 2 log7 x− log 7 x> 4
10 3 log 3 4 log4 2
2 x− x>
11 log3 x− 2 log9x> 2
1
1 3 (log log
4
1 3 1 4
+
≤ +
−
x
x x
x
13 log log2( 4x − 6 ) ≥ 1
x
14 log log3 3 0
3
2 x− ≥
3
1 2 log
2
+
−
x
x
3
1 2 log
2
+
−
x
x
*******************
PT-BPT MŨ LễGARIT QUA ĐỀ THI ĐẠI HỌC 1.(A-08)
4 ) 1 2 ( log ) 1 2
(
1
2 1
2x− x +x− + x+ x− =
Đs;x =2;x=5/4
2.(B-08)
4 (log log0,7 6 2 <
+
+
x
x x
Đs: -4<x<-3; x>8
3.(D-08)
Trang 7Chuyên đề pt,bpt mũ –lôgarits GV: Lơng Thị Lan Phơng
log 3 2 0
2 2
x
x x
ĐS:2 − 2 ≤x< 1 ; 2 <x≤ 2 + 2
4.(A-07)
2log (4 3) log (2 3) 2
3 1
4
3
≤
<x
5.(B-07)
( 2 − 1) (x + 2 + 1)x − 2 2 = 0
ĐSx=1; x=-1
6.(D-07)
0 3 2 4
1 log ) 27 2
.
15
4
(
− +
+
x
Đs: Pt vụ nghiệm
7 (A-06)
0 27 2 18 12
.
4
8
.
3 x + x − x − x =
Đs:x=1
8.(B-06)
) 1 2 ( log 1 2 log 4 )
144
4
(
5 5
5 x + − < + x− +
Đs: 2<x<4
9.(D-06)
0 4 2 2
.
4
2x2+x − x2−x − 2x+ =
ĐS: x=0;x=1
10.(D-03)
2x2−x − 2 2 +x−x2 = 3
ĐS:x=-1;x=2
11.(B-02)
log (log3( 9x − 72 )) ≤ 1
x
ĐS: log3( 6 2 ) <x≤ 2
12.(CĐ-08)
log 2 ( 1 ) 6 log2 1 2 0
2 x+ − x+ + =
13.(Luật HN-98)
( 7 + 4 3 ) cosx + ( 7 − 4 3 ) cosx = 4
3 log 3 ) 12 7 ( log ) 2 3
(
2
2
2 x + x+ + x + x+ = + 15
.(YHN-97)
log2x64 + logx216 ≥ 3
16.(SPHN-D-00)
3 2x − 8 3 x+ 4 +x − 9 9 x+ 4 = 0
2 2x2+ 1 − 9 2x2+x + 2 2x+ 2 = 0
18.(YHN-00)
2
12 2
1 2
6
23x − x − 3(x−1) + x =
log( 10 ) log( 10 ) log( 100 2)
3 2 6
4 x ≤ 3 2 x+x + 4 x+1
21.(HVBCVT-98)
3 1 23 1 12 2
x x
x+ − + <
22 (YHN-99)
2 2x + 3 3x > 6x − 1
23.(TCKT-01)
1 3
1 log log 2 2 3
1 2 log 2 3 1 2
3
≥
+
+ x−
x
24 (Dược-01)
2 1 2
2
x
25.(YHN-01) log2( x2 + 3 −x2 − 1 ) + 2 log2x≤ 0
26 (HVQHQT-01)
2
2 3 log >
+
+
x
x
x
27 (ĐHNN-99)
1 − >
x
) 1 ( log 1 1 2
1 log
) 1 ( log 2
5 1 5
25 x− ≥ x− − x− 29
) 2 3 2 ( log 1 ) 2 3 2 (
2
2
4 x + x+ + > x + x+ 30 (TCKT-99)
x
x
2 1 2
2
3 2 2 1
4
2 9 log 32 4 log
8 log
2
1 x − x+ ≥
32.( ĐHQGHN-A99)
1
1 8 log
2
+
+ +
x
x x
33.(BCVT-99)
Trang 8Chuyên đề pt,bpt mũ –lôgarits GV: Lơng Thị Lan Phơng
log22+log24x=3
x
34.(YHN_99)
225 log 3 log log
log5x+ 3x= 5 9
35.(TSNT-99)
0 2 ) 1 4 4 ( log ) 1 5 6
(
3 1
2
2
1− x x − x+ − −x x − x+ − =
log2x− log4x= −67
3 8
2
2
4 ( 1 ) 2 log 4 log ( 4 )
ĐHQGHN_00)
log5x= log7(x+ 2 )
3 log 2
1 log
2
1 ) 6 5
(
9 x − x+ = x− + x− 40.
(AN-01)
) 1 ( log 2 2 log
1 )
1
3
(
3
+
x x
x
41.(SPVinh-A01)
) 1 (
log
) 1 (
log ).
1 (
log
2 20
2 5
2
4
−
−
=
=
− +
−
−
x x
x x x
x
log 2( 2 +x) + log 2+x x= 2
x
43.(KTQD-01)
4 ) 21 23 6
( log ) 9 12
4
(
log3x+7 x2+ x+ + 2x+3 x2+ x+ =
44.(D-10)
4 4 2
2 2
4 x+ x+ + x = + x+ + x+ x−