Question

xy+y(квадрат)=10
x-y=1
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Answer 1

$\left \{ {{xy+y^{2}=10} \atop {x-y=1}} \right.$
$\left \{ {{y(x+y)=10} \atop {x=1+y}} \right.$
$\left \{ {{y+y^2+y^2=10} \atop {x=1+y}} \right.$
$\left \{ {{2y^2+y-10=0} \atop {x=1+y}} \right.$
$2y^2+y-10=0$
$D=b^2-4ac$
D=1+80=81 > 0
$x_{1} = \frac{-b+ \sqrt{D} }{2a} = \frac{-1+9}{4} =2$
$x_{2}= \frac{-b- \sqrt{D} }{2a} = \frac{-1-9}{4}= -2,5$
$y_{1}=x_{1}-1=2-1=1$
$y_{2}=x_{2}-1=-2.5-1=-3.5$