3y + 6x = 15 9y - x = 11 _____ Multiply the second eqution by 6: 3y + 6x = 15 54y - 6x = 66 _____ Sum up two equations: 3y + 54y = 15 + 66 57y = 81 y = 81/57 y = (81 : 3)/(57 : 3) y = 27/19
Use the second equation to calculate x: 9y - x = 11 x = 9y - 11 x = 9 * 27/19 - 11 x = 243/19 - 11 * 19/19 x = 243/19 - 209/19 x = (243 - 209)/19 x = 34/19
