Question

if 2x+y=17 and xy =35 evaluate 8x3+y3
​

Answer 1

2x+y=17

xy=35

By cubing both sides,we get-----

(2x+y)³=(17)³

(2x)³+(y)³+3×2x×y(2x+y)=4046

8x³+y³+6xy(2x+y)

8x³+y³+6×35(17)=4046

8x³+y³+3570=4046

8x³+y³=4046-3570

8x³+y³=476