用因式分解法解 2（x-3）²=x²-9

用因式分解法解 2（x-3）²=x²-9
用因式分解法解 2（x-3）²=x²-9

用因式分解法解 2（x-3）²=x²-9
2（x-3）²=x²-9
2(x-3)²-(x²-9)=0
2(x-3)²-(x-3)(x+3)=0
(x-3)(2x-6-x-3)=0
(x-3)(x-9)=0
x=3或x=9

2(x-3)²=x²-9
2(x-3)²=(x+3)(x-3)
2(x-3)²-(x+3)(x-3)=0
2(x-3)[(x-3)-(x+3)]=0
所以x-3=0或-6=0(舍去)
x=3