Question

Check whether the following is solution of the equation $x-2y=4$ or not:
$(\sqrt{2},4\sqrt{2})$

Answer 1

If $(\sqrt{2},4\sqrt{2})$ is solution of equation $x-2y=4$, then it must satisfy the equation.

Therefore,

$\sqrt{2}-2\times 4\sqrt{2}=-7\sqrt{2}\ne 4$

Hence $(\sqrt{2},4\sqrt{2})$ is not a solution of equation $x-2y=4$.