[（x-y）²]³·（x-y）·[（x-y）³]的四次方

[（x-y）²]³·（x-y）·[（x-y）³]的四次方

[(x-y)^6*(x-y)*(x-y)^3]^4
=[(x-y)^10]^4
=(x-y)^40

[(x-y)^2]^3.(x-y).[(x-x)^3]^4=(x-y)^6.(x-y).(x-y)^12.
原式＝(x-y)^(6+1+12).
=(x-y)^19.