Question

If x-2y=11 and xy=8,find the value of x^3-8y^3

Answer 1

Answer:

x-2y=11

cubing both sides,

x³-8y³-3.x.2y(x-2y)=1331

or, x³-8y³-6.8.11=1331[•.•, xy=8 and x-2y=11]

or, x³-8y³=1331+528

or, x³-8y³=1859