3(x+1)^2-5(x+1)(x-1)+2(x-1)^2等于多少?
问题描述:
3(x+1)^2-5(x+1)(x-1)+2(x-1)^2等于多少?
答
3(x+1)²-5(x+1)(x-1)+2(x-1)²
=[(x+1)-(x-1)][3(x+1)-2(x-1)]
=2(x+5)
=2x+10