Question

refer the attachment q.21

Answer 1

3x+2y=20

Cubing both sides,

(3x+2y)³=20³

or, (3x)³+(2y)³+3.3x.2y(3x+2y)=8000

or, 27x³+8y³+18xy(20)=8000 [∵, 3x+2y=20]

or, 27x³+8y³+18×11/9×20=8000 [∵, xy=11/9]

or, 27x³+8y³+2×220=8000

or, 27x³+8y³+440=8000

or, 27x³+8y³=8000-440

or, 27x³+8y³=7560