Question

Помогите, пожалуйста! Вопрос на фото.

Answer 1

+$\left \{ {{2x-xy=5} \atop {y+xy=6}} \right.$
_____________________
2x + y = 11
y = 11 - 2x

$\left \{ {{y=11-2x} \atop {2x-x*(11-2x)=5}} \right. \\\\ \left \{ {{y=11-2x} \atop {2x-11x+2 x^{2} =5}} \right.\\\\ \left \{ {{y=11-2x} \atop {2 x^{2} -9x-5=0}} \right.\\\\ \left \{ {{ x_{1}=5 } \atop { y_1={11-2*5} }} \right.\\\\ \left \{ {{ x_{1} =5} \atop { y_{1}=1 }} \right.\\\\ \left \{ {{ x_{2}=-0,5 } \atop { y_{2} =11-2*(-0,5)}} \right.\\\\ \left \{ {{ x_{2}=-0,5 } \atop { y_{2}=12 }} \right.\\\\| x_{1} y_{1}- x_{2} y_{2}|= |5*1-(-0,5)*12|=|5+6|=11$