Question

Выполни и пришли на проверку:
1.
{x/2+y/4=2
{2x-5y/3=-10
2.
{7x/3+y/9=4
{8x/5+y/30=3
ПОМОГИТЕ ПЖ

Answer 1

№1.

$\left \{ {{\frac{x}{2}+\frac{y}{4}=2} \atop {2x-\frac{5y}{3} =-10}} \right.$ →$\left \{ {{2x+y=8} \atop {6x-5y=-30}} \right.$ → $\left \{ {{y=8-2x} \atop {6x-5(8-2x)=-30}} \right.$ →$\left \{ {{y=8-2x} \atop {6x-40+10x=-30}} \right.$ → $\left \{ {{y=8-2x} \atop {16x=40-30}} \right.$ → $\left \{ {{y=8-2x} \atop {16x=10}} \right.$ → $\left \{ {{y=8-2x} \atop {x=\frac{10}{16} }} \right.$ → $\left \{ {{y=8-2*\frac{5}{8} } \atop {x=\frac{5}{8} }} \right.$ → $\left \{ {{y=8-\frac{5}{4} } \atop {x=\frac{5}{8} }} \right.$ →$\left \{ {{y=7\frac{4}{4} -1\frac{1}{4} } \atop {x=\frac{5}{8} }} \right.$ → $\left \{ {{y=6\frac{3}{4}} \atop {x=\frac{5}{8} }} \right.$

Ответ: $(\frac{5}{8}; 6\frac{3}{4} )$

№2.

$\left \{ {{\frac{7x}{3} +\frac{y}{9} =4} \atop {\frac{8x}{5} +\frac{y}{30} =3}} \right.$ → $\left \{ {{21x +y =36} \atop {48x +y=90}} \right.$ → $\left \{ {{-21x -y =-36} \atop {48x +y=90}} \right.$ → $\left \{ {{27x =54} \atop {48x +y=90}} \right.$ → $\left \{ {{x =2} \atop {48*2 +y=90}} \right.$ → $\left \{ {{x =2} \atop {96 +y=90}} \right.$ → $\left \{ {{x =2} \atop {y= -6}} \right.$

Ответ: (2;-6)