[tex](-9b^2a^3)^2 \cdot (3^3b)^2 = (-9)^2\cdot(b^2)^2 \cdot (a^3)^2 \cdot (3^3)^2\cdot (b)^2 = \\ \\= 81\cdot b^4\cdot a^6 \cdot 3^6\cdot b ^2 = 3^4 \cdot a^6 \cdot b^4\cdot 3^6\cdot b ^2 =\\ \\= 3^{4+6} \cdota^{6} \cdot b ^{4+2} = 3^{10} \cdot a^{6} \cdot b ^6[/tex]