Question

Simplify
(5x-7y)^3+(5x+7y)^3
can anyone help in solving briefly this question ​

Answer 1

Answer:

250x^3 + 1470xy^2

Step-by-step explanation:

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

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

So,

(5x-7y) ^3 +(5x+7y)^3

= [(5x)^3-(7y)^3-3×(5x)^2×7y+3×5x×(7y)^2] + [(5x)^3+(7y)^3+3×(5x)^2×7y+3×5x×(7y) ^2]

= [125x^3-343y^3-525x^2y+735xy^2] + [125x^3+343y^3+525x^2y+735xy^2]

=125x^3+125x^3+735xy^2+735xy^2

=250x^3+1470xy^2 (Ans)