# What is the value of x?What is the answer in simplest form?

$x = 9$
${x}^{2} + {x}^{2} = {\left(9 \sqrt{2}\right)}^{2}$
$2 {x}^{2} = 81 \times 2$
${x}^{2} = 81$
$x = \sqrt{81} = 9$