Question

(7x+5y)^3-(7x-5y)^3-30y(7x+5y)(7x-5y)

Answer 1

. · (7x+5y)^3 - (7x-5y)^3 - 30y ( 7x+5y) (7x-5y) = a^3 - b^3 - 30y (ab) = (a-b)^3 + 3ab(a-b) - 30aby = (10y)^3 + 3ab(10y) - ...

Answer 2

(7x + 5y)^3 = 343x^3 + 125y^3 + 735x^2y + 525xy^2

(7x - 5y)^3 = 343x^3 - 125y^3 - 735x^2y - 525xy^2

30y(7x + 5y)(7x - 5y) = 30y(49x^2 - 25y^2) = 1470x^2 - 750y^2

=343x^3 + 125y^3 + 735x^2y + 525xy^2 - 343x^3 - 125y^3 - 735x^2y - 525xy^2 - 1470x^2 - 750y^2

-1470x^2 - 750y^2. - Answer