Question

Evaluate using the identities : ${\left(99\right)}^2-{\left(98\right)}^2$

Answer 1

Step 1: Identify the identity we can use to simplify the question

If we take $a=99andb=98$, the we can clearly see the form of the identity it is taking, it is taking the form of ${\left(a\right)}^2-{\left(b\right)}^2$ which is equal to $(a+b)(a-b)$

Step 2: Solve the question using the identity

$$\begin{gathered} {\left(99\right)}^2-{\left(98\right)}^2=(99+98)(99-98) \\ =\left(197\right)\left(1\right) \\ =197 \end{gathered}$$

Hence, the result is $197$.