Question

Use a suitable identity to get following products

$\left(2y+5\right)\left(2y+5\right)$

Answer 1

Solving $\left(2y+5\right)\left(2y+5\right)={\left(2y+5\right)}^2$:

Using ${(a+b)}^2=a^2+b^2+2ab$

$$\begin{gathered} {\left(2y+5\right)}^2={\left(2y\right)}^2+5^2+2\times 2y\times 5 \\ {\left(2y+5\right)}^2=4y^2+25+20y \end{gathered}$$

Hence, $\left(2y+5\right)\left(2y+5\right)=4y^2+25+20y$.