Question

Вычислить значение дроби $frac{3xz+ x^{2} -2xy}{4 y^{2}-yz-2 z^{2} }$ 



















при условии,что$frac{x}{z}$

=-2, ${z}{y}$

=-1     

Answer 1

$frac{3xz+ x^{2}-2xy }{4y ^{2}-yz-2z ^{2} } =[x=-2z]= frac{3(-2z)z+(-2z) ^{2}-2(-2z)y }{4y ^{2}-yz-2z ^{2} } =$,

$= frac{-6z ^{2}+4z ^{2}+4zy }{4y ^{2}-yz-2z ^{2} }=[z=-y]= frac{-2y ^{2} -4y ^{2} }{4y ^{2}+y ^{2} -2y ^{2} } = frac{-6y ^{2} }{3y ^{2} } =-2$