7x-3(2x-9)=32解方程 解方程(1)x-2x=1-2/3x (2)x-3x-1.2=4.8-5x (3)-x=1-2x (4)2x-x+3=1.5-2x
解方程(1)x-2x=1-2/3x (2)x-3x-1.2=4.8-5x (3)-x=1-2x (4)2x-x+3=1.5-2x
解方程(1)x-2x=1-2/3x (2)x-3x-1.2=4.8-5x (3)-x=1-2x (4)2x-x+3=1.5-2x
1)-x=1-2/3x
-1/3x=1
x=-3
2)-2x-1.2=4.8-5x
3x=6
x=2
3)x=1
4)x+3=1.5-2x
3x=-1.5
x=-0.5
解方程:(1)2x 2 -3x=1(2)(x+3) 2 =(1-2x)
(1)2x 2 -3x-1=0,a=2,b=-3,c=-1,
b 2 -4ac=9+8=17>0;
x= -b± b 2 -4ac 2a = 3± 17 4
;
x 1 =
,x 2 =
3- 17 4;
(2)(x+3) 2 -(1-2x) 2 =0,
(x+3+1-2x)(x+3-1+2x)=0,
(4-x)(3x+2)=0,
4-x=0或3x+2=0,
x 1 =4,x 2 =-
.
解方程:(1)x2-3x+1=0;(2)x(2x-1)=3(1-2x)
(1)∵a=1,b=-3,c=1
∴b2-4ac=(-3)2-4×1×1=5
,x2=
3? 5 2,
(2)x(2x-1)+3(2x-1)=0,
∴(2x-1)(x+3)=0,
∴2x-1=0或x+3=0,
所以x1=-3,x2=
.
解方程(1)(x+3) 2 =(1-2x) 2 (2)3x(x-1)=2-2x(3) ( 1 3 ) -1 -|-2+ 3
(1)∵x+3=±(1-2x),∴x 1 =- 2 3 ,x 2 =-4;
(2)∵3x(x-1)+2(x-1)=0,
∴(x-1)(3x+2)=0,
∴x-1=0或3x+2=0,
∴x 1 =1,x 2 =-
.
(3)原式=3-|-2+
3×1|+2
=3-(2-
)+2
=3-2+
+2
=3+
;
(4)原式=4×
1 2+2
3×
3 2+1
=2+3+1
=6.
解方程:3x(2x-1)=-6(1-2x
移项得:3x(2x-1)-6(2x-1)=0,
分解因式得:(2x-1)(3x-6)=0,
2x-1=0,3x-6=0,
解得:x1=
,x2=2.
解方程:4又1 3X(1 +x)=6 6(3x-2)-2x=1 --x -2x=4.4 --- 5 4
(1) 4.2x-2x=4.4 (2)3(0.25+x)=6 (3)6(3x-2)-2x=1
解: 2.2x=4.4 0.25+x=2 18x-12-2x=1
x=2 x=1.75 16x=13
x=13/16
解方程:(1)3x?1=2x(2)2x+2+3x?2=12x2?
(1)方程两边同乘以x(x-1),
得2(x-1)=3x,
解得x=-2.
经检验:x=-2是原方程的解;
(2)方程两边同乘以(x+2)(x-2),
得2(x-2)+3(x+2)=12,
解得x=2.
经检验:x=2是原方程增根,原方程无解.
解方程:(1)x 2 -2x-8=0;(2)2x 2 -5x+1=0;(3) 2x 2x-1 + 5 1-2x =3 ;(4)
(1)∵x 2 -2x-8=0,∴(x-4)(x+2)=0,
∴x-4=0或x+2=0,
解得:x 1 =4,x 2 =-2;(2)∵2x 2 -5x+1=0,
∴a=2,b=-5,c=1,
∴△=b 2 -4ac=(-5) 2 -4×2×1=17,
∴x= -b± △ 2a
=
5± 17 4,
∴x 1 =

5+ 17 4
,x 2 =
5- 17 4;
(3)方程两边同乘以(2x-1),得:2x-5=3(2x-1),
解得:x=-
,
检验:当x=-
时,2x-1=-2≠0,即x=-
1 2是原分式方程的解,
则原分式方程的解为:x=-
;
(4)方程两边同乘以x(x-1),得:x 2 +x-2=x 2 -x,
解得:x=1,
检验:当x=1时,x(x-1)=0,即x=1不是原分式方程的解,
则原分式方程无解.
解方程(1)2x 2 +3x-1=0(2) x 2 +1 x + 2x x 2 +1 =3
(1)2x 2 +3x-1=0,b 2 -4ac=9-4×2×(-1)=17>0,
∴x= -b± b 2 -4ac 2a = -3± 17 4
,
∴x 1 =
,x 2 =
-3- 17 4;
(2)
x 2 +1 x+
2x x 2 +1=3 ,
假设
=y,
∴y+
=3,
整理得:
y 2 -3y+2=0,
(y-1)(y-2)=0,
y 1 =1,y 2 =2,
∴
=1,
∴x 2 -x+1=0,
b 2 -4ac=1-4×1×1=-3<0,
∴此方程无解;
=2,
∴x 2 -2x+1=0,
b 2 -4ac=4-4×1×1=0,
∴此方程有两个相等的实数根;
∴x=-
=1,
即:x 1 =x 2 =1.
解方程:(1) 10 x = 3 x-7 ;(2) 2x 2x-1 + 5 1-2x =3 ;(
(1)去分母得:10x-70=3x,解得:x=10,
经检验x=10是分式方程的解;(2)去分母得:2x-5=6x-3,
解得:x=- 1 2
,
经检验x=-
是分式方程的解;
(3)去分母得:(6x-1)(2x-5)=(4x-7)(3x+2),
整理得:-19x=-19,
解得:x=1,
经检验x=1是分式方程的解;
(4)去分母得:(x-2) 2 -16=(x+2) 2 ,
整理得:8x=-16,
解得:x=-2,
经检验x=-2是增根,原分式方程无解.