Question

A=13−2√42

Answer 1

`A=13-2\sqrt{42}`

`A=(\sqrt{7})^2-2\sqrt{7}.\sqrt{6}+(\sqrt{6})^2`

`A=(\sqrt{7}-\sqrt{6})^2`

Answer 2

A=13−2√42

\(=\left(\sqrt{7}\right)^2-2\sqrt{7}\cdot\sqrt{6}+\left(\sqrt{6}\right)^2=\left(\sqrt{7}-\sqrt{6}\right)^2\)