Answer
See explanations.
Work Step by Step
Let $ax-by$ be a binomial difference.
Using the formula $(A-B)^2=A^2-2AB+B^2$, we have
$(ax-by)^2=(ax)^2-2(ax)(by)+(by)^2=a^2x^2-2abxy+b^2y^2$.
For example,
$(2x-3y)^2=(2x)^2-2(2x)(3y)+(3y)^2=4x^2-12xy+9y^2$
