谁帮我解这三个一元二次方程?

来源:百度知道 编辑:UC知道 时间:2024/05/23 00:05:27
1.(2x-3)²=9(2x+3)²
2.(5x-1)²=3(5x-1)
3.(x+1)²=-(x+1)+56

要用最简便的方法
要有过程

1.(2x-3)²=9(2x+3)²
(2x-3)²=(6x+9)²
(2x-3)²-(6x+9)²=0
(2x-3+6x+9)(2x-3-6x-9)=0
(8x+6)(-4x-12)=0
x=-3/4,x=-3

2.(5x-1)²=3(5x-1)
(5x-1)²-3(5x-1)=0
(5x-1)(5x-1-3)=0
(5x-1)(5x-4)=0
x=1/5,x=4/5

3.(x+1)²=-(x+1)+56
令a=x+1
则a²+a-56=0
(a-7)(a+8)=0
a=7,a=-8
x=a-1
所以 x=6,x=-9

1.(2x-3)²=9(2x+3)²
(2x-3)²-(6x+9)²=0
(2x-3+6x+9)*(2x-3-6x-9)=0
(4x-3)*(4x+12)=0
4x-3=0.....x=3/4
4x+12=0....x=-3
2.(5x-1)²=3(5x-1)
(5x-1)²-3(5x-1)=0
(5x-1)*(5x-4)=0
5x-1=0.....x=1/5
5x-4=0.....x=4/5
3.(x+1)²=-(x+1)+56
(x+1)²+(x+1)-56=0
(x+1-7)*(x+1+8)=0
(x-6)*(x+9)=0
x-6=0.....x=6
x+9=0.....x=-9