Question

xcube - 8ycube - 36xy - 216, when x=2y+6​

Answer 1

Here's Ur Answer Mate!

x=2y+6

x^3-8y^3-36xy-216

=(2y+6)³−8y³−36(2y+6)y−216

=8y³+6³ +3×(2y)²×6+3×2y×6² −8y³−72y²−216y−216

=8y³+216 +3×4y²×6+3×2y×36−8y³ −72y²−216y−216

=8y³+216 +72y²+216y−8y³ −72y²−216y−216

=8y³−8y³ +72y²−72y²+216y −216y+216−216

=0

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