Question

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Answer 1

$\displaystyle\bf\\x^{3} -x-yx^{2} +y=(x^{3} -yx^{2} )-(x-y)=x^{2} (x-y)-(x-y)=\\\\=(x-y)(x^{2} -1)=(x-y(x-1)(x+1)\\\\x=1 \ \ \ ; \ \ \ y=-3\frac{6}{7} \\\\\\\Big(x-y\Big)\Big(x-1\Big)\Big(x+1\Big)=\Big(1-(-3\frac{6}{7} )\Big)\cdot\underbrace{\Big(1-1\Big)}_{0}\cdot\Big(1+1\Big)=0$