Question

if 2 X + Y is equals to 5 prove that 8 x cube + y cube minus 30 X Y + 125 is equals to zero​

Answer 1

Step-by-step explanation:

$2x + y = 5 \\ cubing \: both \: sides \\ ( {2x + y)}^{3} = ( {5})^{3} \\ {(2x)}^{3} + {y}^{3} + 3 \times 2x \times y(2x + y) = 125 \\ 8 {x}^{3} + {y}^{3} + 6xy(2x + y) = 125 \\ 8 {x}^{3} + {y}^{3} + 6xy \times 5 = 125 \\ 8 {x}^{3} + {y}^{3} + 30xy = 125 \\ 8 {x}^{3} + {y}^{3} + 30xy - 125 = 0 \\ \\ in \: order \: to \: prove \: \\ 8 {x}^{3} + {y}^{3} + 30xy + 125 = 0 \\ we \: should \: have \: 2x + y = \: - \: 5 \\ thus \: question \: needs \: improvement \:$

Answer 2

Answer:

explanation:

\begin{gathered}2x + y = 5 \\ cubing \: both \: sides \\ ( {2x + y)}^{3} = ( {5})^{3} \\ {(2x)}^{3} + {y}^{3} + 3 \times 2x \times y(2x + y) = 125 \\ 8 {x}^{3} + {y}^{3} + 6xy(2x + y) = 125 \\ 8 {x}^{3} + {y}^{3} + 6xy \times 5 = 125 \\ 8 {x}^{3} + {y}^{3} + 30xy = 125 \\ 8 {x}^{3} + {y}^{3} + 30xy - 125 = 0 \\ \\ in \: order \: to \: prove \: \\ 8 {x}^{3} + {y}^{3} + 30xy + 125 = 0 \\ we \: should \: have \: 2x + y = \: - \: 5 \\ thus \: question \: needs \: improvement \: \end{gathered}2x+y=5cubingbothsides(2x+y)3=(5)3(2x)3+y3+3×2x×y(2x+y)=1258x3+y3+6xy(2x+y)=1258x3+y3+6xy×5=1258x3+y3+30xy=1258x3+y3+30xy−125=0inordertoprove8x3+y3+30xy+125=0weshouldhave2x+y=−5thusquestionneedsimprovement