Question

(4a+7b)^3 factorise this​
and
(3x-5y)^3

Answer 1

Answer:

(a+b) ^3 = a^3+b^3+3ab(a+b)

(4a+7b)^3 = (4a)^3+(7b)^3+3×4a×7b(4a+7b)

=64a^3+343b^3+84ab(4a+7b)

=64a^3+343b^3+336a^2b+588ab^2

(a-b)^3= a^3-b^3-3a^2b+3ab^2

(3x-5y)^3 = (3x)^3-(5y)^3-3(3x)^2(5y)+3(3x)(5y)^2

=27x^3-125y^3-135x^2y+225xy^2