Question

2х+4у=1 3х-3у=2 решительно методом сложения

Answer 1

$\left \{ {{-2x+4y=1} \atop {3x-3y=2}} \right.$⇒$\left \{ {{-2x*3+4y*3=1*3} \atop {3x*2-3y*2=2*2}} \right.$⇒$\left \{ {{-6x+12y=3} \atop {6x-6y=4}} \right.$⇒$\left \{ {{6y=7} \atop {y= \frac{7}{6} }} \right.$

$6x-6y=4$
$6x-6* \frac{7}{6} =4$
$6x-7=4$
$6x=4+7$
$6x=11$
$x= \frac{11}{6}$

$y= \frac{7}{6}$     $x= \frac{11}{6}$

Проверка:
$\left \{ {{-2* \frac{11}{6} +4* \frac{7}{6} =1} \atop {3* \frac{11}{6}-3* \frac{7}{6}=2}} \right.$⇒$\left \{ {{- \frac{11}{3}+ \frac{14}{3} =1} \atop { \frac{11}{2}- \frac{7}{2} =2}} \right.$⇒$\left \{ {{1=1} \atop { \frac{4}{2} =2}} \right.$