factoring this equation

Variable change: z=xy

As a result of substitution, you will get the following expression:

1-z-20z

^{2}. If you need to factor this, use quadratic formula:^{ }z

_{1,2}=-[1±√(1+20*4)]/40=-(1±9)/40z

_{1}=-1/4; z_{2}=1/5; Therefore1-z-20z

^{2}=(1-5z)*(4z+1)Substituting xy for z, we will obtain final factoring:

**1-xy-20x**

^{2}y^{2}=(1-5xy)*(4xy+1)Since you did not specify what the equation is, I would leave the rest to you.