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17If 2x +y-17 and xy35, evaluate 8x3-ัะท, here?x>y.fi 3 |
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Answer» 2x+y=17----------(1)xy=35=>x=35/y----------(2) Substitute equation (2) in (1);70/y +y=17=>y²-17y+70=0=>y²-10y-7y+70=0=>y(y-10)-7(y-10)=0=>(y-10)(y-7)=0=>y=10 or 7 Now from equation (2);x=3.5 or 5 ∴8x³-y³=8(3.5)³-10³ or 8(5)³-7³=-657 or 657 thanks |
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