2(x-y)^2-6(x-y)+8(y-x)^2+5(y-x)其中x-y=5求化简求值,先同类项
问题描述：
2(x-y)^2-6(x-y)+8(y-x)^2+5(y-x)其中x-y=5求化简求值,先同类项
答
解
2(x-y)²-6(x-y)+8(y-x)²+5(y-x)
=2(x-y)²-6(x-y)+8(x-y)²-5(x-y)
=(2+8)(x-y)²+(-6-5)(x-y)
=10(x-y)²-11(x-y)
=10×25-11×5
=250-55
=195
答
2(x-y)^2-6(x-y)+8(y-x)^2+5(y-x)
=10(x-y)²-11(x-y)
当x-y=5时
原式=10×5²-11×5=195