Question

√81x^4
I need to know how to solve it to

Answer 1

$\sqrt{81x^4}=\sqrt{81}\cdot\sqrt{x^4}=9x^2$

Answer 2

$\sqrt{81x^4}=\sqrt{81}\cdot\sqrt{x^4}=\sqrt{9^2}\cdot\sqrt{(x^2)^2}=\boxed{9x^2}\\\\use:\sqrt{a^2}=a\ where\ a \geq 0$