Question

Subtract 7p(3q + 7p) from 8p(2p -7q)

Answer 1

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

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

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

Answer 2

$\large \mathfrak{Solution : \implies }$

$\sf\star \: ғɪʀsᴛ \: sᴏʟᴠɪɴɢ \: ʟʜs \star \\ \: \\ \implies \sf \: 8p \bigg(2p - 7q \bigg) \\ \\ \sf \implies16 {p}^{2} - 56 {pq}$

$\star \sf \: ɴᴏᴡ \: \: sᴏʟᴠɪɴɢ \ \: ʀʜs \: \: \star \: \\ \\ \sf \implies7p \bigg( 3q + 7p\bigg) \\ \\ \sf\implies \: 21pq \: + 14 {p}^{2}$

Now subtracting both the sides :-

$\: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \sf \implies16 {p}^{2} - 56pq(21pq + 14 {p}^{2} ) \\\\ \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \implies \sf {16p}^{2} - 56pq - 21pq - 14 {p}^{2} \\ \\ \sf \implies2 {p}^{2} - 77pq$

Hence the answer is 2p^2 - 77pq