Explanation: The second equation given is: x - y = 3 This can be rewritten as: x = y + 3 .........> I The first given equation is: 2x + y = 15 ..........> II
Substitute with I in II and solve for y as follows: 2x + y = 15 2(y+3) + y = 15 2y + 6 + y = 15 3y = 15 - 6 3y = 9 y = 9/3 = 3
Now, substitute with the value of the y in I to get x as follows: x = y + 3 x = 3 + 3 x = 6
