Question

Find the value of x³ - 8y³ - 36xy when x = (2y + 6)(2y + 6 - 2y)³ Please answer correctly. Spams will be reported.​

Answer 1

Answer:

.

(x-2y) = 6

Cubing on both sides

(x-2y)3 = 63

(a-b)3 = a3- 3a?b+3ab2-b3

Comparing (x-2y) with (a-b) a=x b=2y =63

(x-2y)3

x3- 3x2*2y+3x(2y)²-(2y)³= 216

x3- 6x2y+12xy2-8y3=216

x3+6xy(2y-x)-8y³=216

2y-x = 6

So,

х3-6ху (2y-x)-8y3-216

x3-6xy*6-8y3=216

x3-36xy-8y3-216=0

So,

x3-8y3-36xy-216 = 0