计算2(x-y)的平方+8(y-x)的平方-(y-x)的立方+(x-y)的立方,其中x-y=2
问题描述:
计算2(x-y)的平方+8(y-x)的平方-(y-x)的立方+(x-y)的立方,其中x-y=2
答
34
答
2(x-y)^2+8(y-x)^2-(y-x)^3+(x-y)^3
=2(x-y)^2+8[-(x-y)]^2-[-(x-y)]^3+(x-y)^3
=2*2^2+8*[-2]^2-[-2]^3+2^3
=8+32+8+8
=64