Question

памагите развизать х-2у=5 х+у=4

Answer 1

Ответ:

$\displaystyle (x;y)=(4\frac{2}{3};-\frac{1}{3} )$

Объяснение:

$\displaystyle \left \{ {{x-2y=5} \atop {x+y=4}} \right. < = > \left \{ {{x = 5+2y} \atop {5+2y+y=4}} \right. < = > \left \{ {{x = 5+2y} \atop {3y=-1|:3}} \right. < = > \\ < = > \left \{ {{x=5+2*(-\frac{1}{3} )} \atop {y=-\frac{1}{3} }} \right. < = > \left \{ {{x=5-\frac{2}{3} } \atop {y=-\frac{1}{3} }} \right. < = > \left \{ {{x=4\frac{1}{3} } \atop {y=-\frac{1}{3} }} \right.$