Question

If 5^-x=3 what does 5^3x equal?

Answer 1

The answer is 1/27


$5^{-x} = 3 \\ \\ \frac{1}{ 5^{x} } =3 \\ \\ 1 = 3* 5^{x} \\ \\ 5^{x} = \frac{1}{3} \\ \\ (5^{x})^{3} = (\frac{1}{3})^{3} \\ \\ 5^{x*3}= \frac{1^{3}}{3^{3}} \\ \\ 5^{3x}= \frac{1}{27}$

Answer 2

5 to the -x = 3 > which means that -x equals -.68260619
Plug in -.68260619 for x: 5 raised to 3x = .03703703
If that's how you intended to solve it then that's the correct answer.