Question

Simplify the following expressions:

`(sqrt5 - sqrt2)(sqrt5 + sqrt2)`

Answer 1

We know that `(a - b)(a + b) =         a^2 - b^2`We will use this property to simplify the expression

`(sqrt5 - sqrt2)(sqrt5 + sqrt2) = (sqrt5)^2 - (sqrt2)^2`

`= sqrt5 xx sqrt5 - sqrt2 xx sqrt2`

`= (5^2)^(1/2) - (2^2)^(1/2)`

`=5^1 - 2^1`

= 3

Hence the value of expression is 3.