Solve the simultaneous equation: 2x + y = 18 and x−y=6

Check to see if the number in front (coefficient) of either the x's or y's is the same. In this case both the y's have the same coefficient so we do not need to make them the same.We are going to add the parts in the questions as the equations in front of y's are different (one is positive and the other is negative)2x + x = 3x and y +- y = 0 (as a + and - = -) and 18+6 = 24. Bringing it all together 3x = 24. Dividing by 3 gives x = 8.We now substitute 8 in for x in one of the equations. So 8-y=6. giving y to = 2 and x to 8.