Решите,пожалуйста.Подробно.
1. $left { {{6x-y=2} atop {-x+y=-1}} right.$
2. $left { {{x+y=-5} atop {-y- x^{2} =5}} right.$
3. $left { {{x-y=6} atop { x^{2} + y^{2} =20}} right.$

1. $+left { {{6x-y=2} atop {-x+y=-1}} right. 6x-y-x+y=2-1 5x=1 x=0,2 y=-1+x y=-1+0,2 y=-0,8 =$

Ответ: $(0,2;-0,8)$

2. $+ left { {{x+y=-5} atop {-y- x^{2} =5}} right. x+y-y-x^2=-5+5 x-x^2=0 x(1-x)=0 x_1=0~~~~~~~~~~~~~~~~~~~~~~~x_2=1 y_1=-5-x_1~~~~~~~~~~~~~~y_2=-5-x_2 y_1=-5-0~~~~~~~~~~~~~~~~y_2=-5-1 y_1=-5~~~~~~~~~~~~~~~~~~~~~y_2=-6 =$

Ответ: $(0;-5);~(1;-6)$

3. $left { {{x-y=6} atop { x^{2} + y^{2} =20}} right. ~~~~ left { {{y=x-6} atop {x^2+(x-6)^2=20}} right. x^2+(x-6)^2=20 x^2+x^2-12x+36=20 2x^2-12x-16=0|:2 x^2-6x-8=0 (x-2)(x-4)=0 =$