Вычислить значение дроби [latex] \frac{3xz+ x^{2} -2xy}{4 y^{2}-yz-2 z^{2} } [/latex]  при условии,что[latex] \frac{x}{z} [/latex]=-2, [latex]{z}{y} [/latex]=-1     

[latex] \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} } =[/latex], [latex]= \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 [/latex]