Question

xa-xb^2-ya+zb^2-za+yb^2

Answer 1

 xa-xb²-ya+zb²-za+yb²=(xa-b²)-(ya-yb²)-(za-zb²)=x(a-b²)-y(a-b²)-z(a-b²)=
=(a-b²)(x-y-z)