Question

Помогите решить линейное уравнение , с помощью подстановки

Answer 1

$\left \{ {{x+3y=18} \atop {2x-3y=3}} \right. \left \{ {{x=18-3y} \atop {2x-3y=3}} \right. \left \{ {{x=18-3y} \atop {2(18-3y)=3+3y}} \right. \left \{ {{x=18-3y} \atop {36-6y=3+3y}} \right. \\ \left \{ {{x=18-3y} \atop {12-2y=1+y}} \right.\\\left \{ {{x=18-3y} \atop {3y=11}} \right.\\ \left \{ {{x=18-3y} \atop {y=\frac{11}{3}} \right. \left \{ {{x=7} \atop {y=\frac{11}{3}} \right.$

Ответ: $(7; \frac{11}{3})$

Answer 2

Решение:
$\left \{ {{x +3 y=18} \atop {2x - 3y=3}} \right.$
$\left \{ {{x=18 - 3y} \atop {2x - 3y=3}} \right.$
$\left \{ {{x=18 - 3y} \atop {2*(18-3y)-3y=3}} \right. , \left \{ {{x=18 - 3y} \atop {36-6y-3y=3}} \right. , \left \{ {{x=18 - 3y} \atop {36-9y=3}} \right. , \left \{ {{x=18 - 3y} \atop {-9y=-33}} \right. , \left \{ {{x=18-11} \atop {3y=11}} \right. ,$ $\left \{ {{x=7} \atop {y=3 \frac{2}{3} }} \right.$
Ответ:$(7;3 \frac{2}{3} )$