Answer:
x = 3
Step-by-step explanation:
[tex] {5}^{2x} \ast {5}^{3} = {5}^{9} \\ {5}^{2x + 3} = {5}^{9} \\ 2x + 3 = 9 \\ (bases \: are \: equal \: so \: exponents \: will \: also \: \\ be \: equal) \\ 2x = 9 - 3 \\ 2x = 6 \\ x = \frac{6}{2} \\ \huge \red { \boxed{x = 3}}[/tex]