因式分解x²+10xy-70y-49
问题描述:
因式分解x²+10xy-70y-49
答
x²+10xy-70y-49
=(x-5y)^2-(5y-7)^2
=(x-5y+5y-7)(x-5y-5y+7)
=(x-7)(x-10y+7)