Question

Factorise $4{\left(m+n\right)}^2-28p\left(m+n\right)+49p^2$ using suitable identity.

Answer 1

$4{\left(m+n\right)}^2-28p\left(m+n\right)+49p^2$

$=2^2{\left(m+n\right)}^2-2\times 7p.2\left(m+n\right)+7^2{p}^2$

$=\left\{2\right(m+n)-7p{\}}^2$.