• Equation 1:  2x + y = 7
• Equation 2: 3x - y = 8

Add the two equations to eliminate the ys: 

• 2x + y = 7
• 3x - y = 8
• ------------
• 5x = 15
• x = 3

• Now you can put x = 3 in either of the equations.
• Substitute x = 3 into the equation 2x + y = 7:
• 6 + y = 7
• y = 1

So the answers are x = 3 and y = 1