To solve a pair of simultaneous equations you need to find the values of x and y which are the same for both equations. To do this you should eliminate one of the unknowns - in this instance it can easily be done by adding the two equations together.2x + y + 3x - y = 7 + 8As you can see, the two y's cancel out leaving 5x = 15. You can then divide both sides of this to give x = 3.Now we need to find the value of y when x = 3. To do this you pick one of the original equations to substitute the new value of x into:2 * 3 + y = 76 + y = 7Subtracting 6 from both sides leaves y = 1.Therefore the solution is x = 3 and y = 1.