easy peasy
just use PEMDAS and some exonential laws
[tex] (x^{m})(x^{n})=x^{m+n} [/tex]
[tex] (x^{m})^{n}=x^{mn} [/tex]
[tex] (ab)^{m}=(a^{m})(b^{m}) [/tex]
also another is [tex] x^{\frac{m}{n}}=\sqrt[n]{x^{m}} [/tex]
so
[tex] [3(2a)^{\frac{3}{2}}]^{2} [/tex]=
[tex] (3^{2})((2a)^{\frac{3}{2}}^{2}) [/tex]=
[tex] (9)((2a)^{\frac{3}{2}}^{2}) [/tex]=
[tex] (9)((2a)^{\frac{6}{2}) [/tex]=
[tex] (9)((2a)^{3}) [/tex] =
[tex] (9)(8a^{3}) [/tex] =
[tex] 72a^{3} [/tex]
