Answer:
ac - ad - bc + bd
Step-by-step explanation:
There aren't very many steps to show, but I'm assuming that you needed to multiply out the equation. So for this, you would use FOIL which means first, inner, outer, last.
I think of it as multiplying the a with c and d, and then multiplying the b with the c and d. When you do this, you get ac - ad - bc + bd.
