Упростите:
A)(a-2b)(b+4a)-7b(a+b);
Б)(p-q)(p+3q)-(p^2+3q^2).

(a-2b)(b+4a)-7b(a+b)=ab+4a²-2b²-2ab-7ab-7b²=4a²-9b²-8ab(p-q)(p+3q)-(p^2+3q^2)=p²-qp+3pq-3q²-p²-3q²=-6q²+2qp