2(x-3)平方=x2-9用因式分解法,
问题描述:
2(x-3)平方=x2-9用因式分解法,
答
2(x-3)²=x²-9
2(x²-6x+9)=x²-9
2x²-12x+18=x²-9
2x²-12x+18-(x²-9)=0
x²-12x+27=0
(x-3)(x-9)=0
x=3,x=9