vw-vx+wz-xz x vw+vx-wz-xz
___________ ___________
kv+nv-kz-nz vw+vx+wz+xz
find the product and put in lowest terms
What you have written is difficult to decipher. Do you want the product
[(vw-vx+wz-xz)/(kv+nv-kz-nz)]*
[vw+vx-wz-xz )/(vw+vx+wz+xz)]?
If so, rewrite it as
[(v-z}(w-x))/(v-z)(k+n)]*
[(v-z)(w+x))/(v+z)(x+w)]
= [(w-x)/(k+n)]*[(v-z)/(v+z)]
= [(w-x)(v-z)]/[(k+z)((v+z)]
Multiply out the numerator and denominator if you wish.