Question

Use a suitable identity to get the products of the following.

$\left(1.1m-0.4\right)\left(1.1m+0.4\right)$

Answer 1

Solving $\left(1.1m-0.4\right)\left(1.1m+0.4\right)$:

Given: $\left(1.1m-0.4\right)\left(1.1m+0.4\right)$

Using the identity, $\left(a-b\right)\left(a+b\right)=a^2-b^2$

We get,

$\begin{array}{rcl}\left(1.1m-0.4\right)\left(1.1m+0.4\right)& =& {\left(1.1m\right)}^2-{\left(0.4\right)}^2\\ & =& 1.21m^2-0.16\end{array}$

Hence, the product of $\left(1.1m-0.4\right)\left(1.1m+0.4\right)$ is $1.21m^2-0.16$