Question

Найдите сумму из системы

Answer 1

Ответ:

$\left \{ {{y^2 - 6y = 0} \atop {x+y = 8}} \right. \\\left \{ {{y^2 - 6y = 0} \atop {x=8-y}} \right. \\y(y-6) = 0\\y_{1} = 0\\ x_{1} = 8-0 = 8\\ x_{1}*y_{1} = 8*0 = 0\\\\y - 6 = 0\\y_{2} = 6\\x_{2} = 8-6 = 2\\y_{2} * x_{2} = 6*2 = 12\\x_{1}*y_{1}+y_{2} * x_{2} = 0+12 = 12$