Step-by-step explanation:
we want to factor the following expression
[tex] \displaystyle px + qx + py + qy[/tex]
to do so group px's and qy's
[tex] \displaystyle px + py + qx + qy[/tex]
factor out p:
[tex] \displaystyle p(x + y ) + qx + qy[/tex]
factor out "q":
[tex] \displaystyle p(x + y ) + q(x + y)[/tex]
group:
[tex]\boxed{ \displaystyle( p+ q)(x + y)}[/tex]
