(3m-2n)^3+(3m+2n)^3

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(3m-2n)^3+(3m+2n)^3

(3m-2n)^3+(3m+2n)^3
(3m-2n)^3+(3m+2n)^3

(3m-2n)^3+(3m+2n)^3
a^3+b^3=(a+b)(a^2-ab+b^2)
(3m-2n)^3+(3m+2n)^3
= (3m-2n + 3m+2n)[(3m-2n)^2 - (3m-2n)(3m+2n) +(3m+2n)^2]
= 6m(9m^2 + 12n^2)
= 54m^3 + 72mn^2