(2x-1)²-9x²＝0

(2x-1)²-9x²＝0
(2x-1)²-9x²＝0

(2x-1)²-9x²＝0
解方程(2x-1)²-9x²=0
(2x-1+3x)(2x-1-3x)=(5x-1)(-x-1)=0
故x₁=1/5；x₂=-1.

(2x-1)^2-9x^2=0
(2x-1+3x)(2x-1-3x)=0
(5x-1）(-x-1)=0
x1=1/5 x2=-1

4x－4x+1-9x=0
-5x-4x+1=0
5x+4x-1=0
(5x-1)(x+1)=0
x=1/5或者x=-1

（2x-1）2-9x2=0
4x2-4x+1-9x2=0
-5x2-4x+1=0
用求根公式可得x1=-1
x2=1/5

x=0.2或-1

x=1,-1,0.2,-0.2