Question

$(3x²+y³)²$(3x²+y³)²

Answer 1

= (3x²+y³)²  
= (3x²+y³).(3x²+y³)

= 9x⁴ + 3x²y³ + 3x²y³ + y⁶
= 9x⁴ + 6x²y³ + y⁶

Answer 2

Wesley, só cheguei até aqui!
(3x²+y³)² =$9 x^{4} +2*3 x^{2} y^{3} + y^{6} = \\ 9 x^{4} +6 x^{2} y^{3} + y^{6}$