5x-2y=1 15x-3y=-3 линейное уравнение

$\left \{ {{5x-2y=1} \atop {15x-3y=-3}} \right.$

$\left \{ {{5x-2y=1} \atop {3y=15x+3}} \right.$

$\left \{ {{5x-2y=1} \atop {y=\frac{15x+3}{3}}} \right.$

$\left \{ {{5x-2y=1} \atop {y=\frac{15x}{3}+\frac{3}{3}}} \right.$

$\left \{ {{5x-2y=1} \atop {y=5x+1}} \right.$

$\left \{ {{y=5x+1} \atop {5x-2\cdot(5x+1)=1}} \right.$

$5x-2\cdot(5x+1)=1$

$5x-10x-2=1$

$-5x-2=1$

$5x=-2-1$

$5x=-3$

$x=-3:5$

$x=-\frac{3}{5}=-0,6$

$y=5\cdot(-0,6)+1=-3+1=-2$

$\left \{ {{x=-0,6} \atop {y=-2}} \right.$

Проверка:

$\left \{ {{5\cdot(-0,6)-2\cdot(-2)=-3+4=1} \atop {15\cdot(-0,6)-3\cdot(-2)=-9+6=-3}} \right.$