Question

Simplify: ${(3pq+3qr)}^2-18p{q}^{2}r$

Answer 1

Given : ${(3pq+3qr)}^2-18p{q}^{2}r$

Expanding ${(3pq+3qr)}^2$ using ${(a+b)}^2=a^2+2ab+b^2$,

${(3pq+3qr)}^2$
= $9{\left(p\right)}^2{\left(q\right)}^2+9{\left(q\right)}^2{\left(r\right)}^2+18p{q}^{2}r$

${(3pq+3qr)}^2-18p{q}^{2}r$
$=9p^2{q}^2+9q^2{r}^2+18p{q}^{2}r-18p{q}^{2}r$

$=9p^2{q}^2+9q^2{r}^2$