Question

2x +3y =13 ,xy=6 find 8x cube+27y cube​

Answer 1

2x+3y=13

(2x+3y)³=13³

8x³+27y³+18xy(2x+3y)=2197

8x³+27y³+18*6*13=2197

8x³+27y³=2197-1404=793

Answer 2

$HEYA \: \\ \\ GIVEN \: \: QUESTION \: \: Is \: \: \\ \\ 2x + 3y = 13 \: \: \: \: \: find \: \: \: 8x {}^{3} + 27y {}^{2} \\ \\ \: cubing \: on \: both \: sides \: we \: have \\ \\ (2x + 3y) {}^{3} = (13) {}^{3} \\ \\ (2x) {}^{3} + (3y) {}^{3} + 3(2x)(3y)(2x + 3y) = 2197 \\ \\ 8x {}^{3} + 27y {}^{3} + 18xy(13) = 2197 \\ \\ 8x {}^{3} + 27y {}^{3} + 234(6) = 2197 \\ \\ 8x {}^{3} + 27y {}^{3} + 1404 = 2197 \\ \\ 8x {}^{3} + 27y {}^{3} = 2197 - 1404 \\ \\ 8x {}^{3} + 27y {}^{3} = 793$