# How do you simplify sqrt (9 x^4) + sqrt (16 x) ?

It is $3 {x}^{2} + 4 \sqrt{x}$
It is $\sqrt{9 {x}^{4}} + \sqrt{16 x} = \sqrt{{\left(3 {x}^{2}\right)}^{2}} + \sqrt{{4}^{2} x} = 3 {x}^{2} + 4 \sqrt{x}$