1.(3x-1)²=4(2x+3)²

题目

1.(3x-1)²=4(2x+3)²
2.4(y-1)²=y(y-1)²
3.25(x-7)²=16(x+4)²
4.0.2x²+0.75x=0
5.2(3x-1)²-18=0
6.(2x-5)²-2x+5=0
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答案

1.(3x-1)²=4(2x+3)²
(3x-1)²-4(2x+3)²=0
(3x-1)²-[2(2x+3)]²=0
[(3x-1)+2(2x+3)]*[(3x-1)-2(2x+3)]=0
(7x+5)*(-x-7)=0
x1=-5/7 ,x2=-7
2.4(y-1)²=y(y-1)²
4(y-1)²-y(y-1)²=0
(y-1)²(4-y)=0
y1=1 ,y2=4
3.25(x-7)²=16(x+4)²
[5(x-7)]2-[4(x+4)]2=0
[5(x-7)+4(x+4)]*[5(x-7)-4(x+4)]=0
(9x-19)*(x-51)=0
x1=19/9 ,x2=51
4.0.2x²+0.75x=0
x(0.2x+0.75)=0
x1=0 ,x2=-3.75
5.2(3x-1)²-18=0
(3x-1)²=9
上式两边分别取根号得：
3x-1=±3
x1=4/3 ,x2=-2/3
6.(2x-5)²-2x+5=0
(2x-5)²-(2x-5)=0
(2x-5)(2x-5-1)=0
(2x-5)(2x-6)=0
x1=5/2 ,x2=3
这几道题都很简单,学数学要多动动脑筋