Question

how would I simplify sqrt(16x)+sqrt(x^9)

Answer 1

~(16x)+~(x^(9))

Pull all perfect square roots out from under the radical. In this case, remove the 4 because it is a perfect square.
4~(x)+~(x^(9))

Pull all perfect square roots out from under the radical. In this case, remove the x^(4) because it is a perfect square.
4~(x)+x^(4)~(x)
4 sqrt(x) +x^4 sqrt(x)