Question

（x-y）^3×（y-x）^4+（x-y）^2×（y-x）^5

Answer 1

（x-y）^3×（y-x）^4+（x-y）^2×（y-x）^5

=(x-y)^3×(x-y)^4+(x-y)^2×[-(x-y)]^5

=(x-y)^7-(x-y)^7

=0