Question

х+1=-у ху+3х-1=0 решите систему

Answer 1

$\tt\displaystyle \left \{ {{x+1=-y} \atop {xy+3x-1=0}} \right. \Longrightarrow \left \{ {{y=-x-1} \atop {xy+3x-1=0}} \right.\\\\\\x(-x-1)+3x-1=0\\\\-x^2-x+3x-1=0\\\\-x^2+2x-1=0|*(-1)\\\\x^2-2x+1=0\\\\D=(-2)^2-4*1*1=4-4=0\\\\x=\frac{2}{2}\\\\x=1 \\\\\----------\\y=-x-1\\\\y=-1-1\\\\y=-2$

Ответ: (1; -2)