Question

(5A + 3 b) -(5 A-3b)

Answer 1

$= (5a) ^{3} + (3b) ^{3} + 3(5a) ^{2}(3b) + 3(5a)(3b) ^{2} -[(5a) ^{3} + ( - 3b) ^{3} + 3(5a) ^{2} ( - 3b) + 3(5a)( - 3b)^{2} ] \\ = 125 {a}^{3} + 27 {b}^{3} + 225 {a}^{2} b + 135a {b}^{2} - [125 {a}^{3} - 27b ^{3} - 225a^{2}b + 135ab ^{2} ] \\ = 125 {a}^{3} + 27 {b}^{3} + 225 {a}^{2} b + 135a {b}^{2} - 125 {a}^{3} + 27b ^{3} + 225a ^{2} b - 135ab ^{2} \\ = 54 {b}^{3} + 450 {a}^{2} b$