分解因式x^2-x-9y^2-3y还有这个12(x+y)^2+11(x^2-y^2)+2(x-y)^2
问题描述:
分解因式x^2-x-9y^2-3y
还有这个12(x+y)^2+11(x^2-y^2)+2(x-y)^2
答
x^2-x-9y^2-3y
=(x^2-9y^2)-x-3y
=(x+3y)(x-3y)-(x+3y)
=(x+3y)(x-3y-1)