Question

Find the volume of cube whose dimensions are (x+7y),(7x-y) and (xy-5). i will mark as brainliest pls answer

Answer 1

Answer:

Volume of the cube is $= 7x^3y - 35x^2 + 48x^2y^2 - 240xy + 35y^2 - 7xy^3$

Step-by-step explanation:

Volume of the cube is the product of it's three dimensions

$=(x + 7y)(7x - y)(xy - 5)$

$= [x(7x - y) + 7y(7x - y)](xy - 5)$

$= (7x^2 - xy + 49xy - 7y^2)(xy - 5)$

$= (7x^2 + 48xy - 7y^2)(xy - 5)$

$= xy(7x^2 + 48xy - 7y^2) - 5(7x^2 + 48xy - 7y^2)$

$= 7x^3y + 48x^2y^2 - 7xy^3 - 35x^2 - 240xy + 35y^2$

$= 7x^3y - 35x^2 + 48x^2y^2 - 240xy + 35y^2 - 7xy^3$