Answer:
54x^3+18xy^2
Step-by-step explanation:
1.) Expand the Expressions
(3x + y)^3 + (3x - y)^3 =====> 27x^3 + 27x^2y + 9xy^2 + y^3 + 27x^3 - 27x^2y + 9xy^2 - y^3
2.) Remove/Cancel out Opposites
27x^3 + 9xy^2 + 27x^3 + 9xy^2
3.) Collect like terms
27x^3 + 9xy^2 + 27x^3 + 9xy^2
54x^3 + 9xy^2 + 9xy^2
54x^3 + 18xy^2
Formulas used :
(a+b)^3 = a^3 + 3a^2b + 3ab^2 +b^3 (step 1)
Thank You!!! Plzz mark brainliest
