Question

помогите пожалуйста с алгеброй​

Answer 1

Ответ:

Объяснение:

$\left \{ {{x=y^2-4y}; \atop {x+y=4}} \right. \left \{ {{x=y^2-4y}; \atop {x=4-y}} \right. \\4-y=y^2-4y;y^2-3y-4=0;\\y_1=-1; x_1=4+1=5;\\y_2=4; x_2=4-4=0$

Answer 2

Ответ:

Объяснение:

$\displaystyle\bf\\\left \{ {{x=y^2-4y} \atop {x+y=4}} \right. \Leftrightarrow\left \{ {{x=y^2-4y} \atop {x=4-y}} \right. \Leftrightarrow\left \left \{ {{4-y=y^2-4y} \atop {x=4-y}} \right.$

$\displaystyle\bf\\\left \{ {{y^2-3y-4=0} \atop {x=4-y}} \right. \Leftrightarrow \left \{ {{(y-4)(y+1)=0} \atop {x=4-y}} \right.$

$\displaystyle\bf\\1)\left \{ {{y=4} \atop {x=4-4}} \right. ;\ \left \{ {{y=4} \atop {x=0}} \right.\\\\\\ 2)\left \{ {{y=-1} \atop {x=4-(-1)}} \right. ;\ \left \{ {{y=-1} \atop {x=5}} \right.$

О т в е т:     $\displaystyle\bf(0;4); \ (5;-1)$