Question

Evaluate following using identities:

(a - 0.1) (a + 0.1)

Answer 1

In the given problem, we have to evaluate expressions by using identities.

The given expression is (a + 0.1)(a - 0.1)

We shall use the identity ${\displaystyle (x+y)(x-y)=x^2-y^2}$

Here x = a

y = 0.1

By applying identity we get 

${\displaystyle (a +0.1)(a-0.1)={\left(a\right)}^2-{\left(0.1\right)}^2}$

${\displaystyle =(a \times a)-(0.1\times 0.1)}$

${\displaystyle =a^2-0.01}$

Hence the value of (a + 0.1)(a - 0.1) is ${\displaystyle a^2-0.01}$