Question

8p(2p-7q)-{7p(3q+7p)

Answer 1

16p^2-56pq-(21pq+49p^2)
16p^2-56pq-21pq-49p^2
-33p^2-77pq
-11p(3p+7q)

Answer 2

$\rm{8p\left(2p-7q\right)-7p\left(3q+7p\right)=16p^2-56pq-7p\left(3q+7p\right)}$

$\longrightarrow\rm{8p\left(2p-7q\right)-7p\left(3q+7p\right)=16p^2-56pq-21pq-49p^2}$

$\longrightarrow\rm{8p\left(2p-7q\right)-7p\left(3q+7p\right)=16p^2-49p^2-56pq-21pq=-33p^2-77pq}$