rozwiąż układ równań metodą podstawiania: 5x - 3y =18 4x + 5y = 7

5x - 3y =18 / *5 4x + 5y = 7 / *3 25 x - 15 y = 90 12x + 15 y = 21 -90 + 25x = 15y 12x - 90 + 25x = 21 37 x = 111 / :3 x = 3 4 * (x = 3) + 5 y = 7 12 + 5y = 7 +5y = - 5 y = -1 x=3 y= -1

{5x - 3y =18/*5 {4x + 5y = 7/*3 {25x-15y=90 {12x+15y=21 25x+12x=90+21 37x=111/:37 x=3 {x=3 {5x - 3y =18 {x=3 {5*3-3y=18 {x=3 {-3y=3 {x=3 {y=-1