Anonymous

5x + y = 19 → given that: x - 3y = 7 → x = 3y + 7 5.(3y + 7) + y = 19 15y + 35 + y = 19 16y = - 16 → y = - 1 Recall: x = 3y + 7 x = - 3 + 7 → x = 4 x + y = 4 - 1 = 3

Anonymous

x + y = (7(5-1) - 19(1--3))/(5×-3 - 1×1) = (28 - 76)/(-15 - 1) = (-48)/(-16) = 3 The correct answer is c. 3

Anonymous

5x + y = 19 x - 3y = 7 15x + 3y = 57 x = 4, y = -1 x + y = 3 Answer choice: c. 3

Anonymous

5x + y = 19 …… [1] x - 3y = 7 …… [2] [1] - [2] : (5x + y) - (x - 3y) = 19 - 7 5x + y - x + 3y = 12 4x + 4y = 12 x + y = 3 The answer: c. 3