Solve the following simultaneous equations to obtain values for x and y: 2x + y = 7 & 3x - y = 8.

Label your equations 1 and 2 respectively. Make y the subject of equation 2 by taking away 3x from both sides and multiplying both sides by -1, to get y = 3x - 8. Now substitute this into equation 1 (i.e. replace the 'y' in equation 1 with '3x - 8'), giving 2x + (3x - 8) = 7. By grouping like terms together and adding 8 to both sides we get 5x = 15. Now to obtain our value of x simply divide both sides by 5, hence x = 3. Now use this value of x to find y. Substitute x = 3 into equation 2. So 3(3) - y = 8. This gives 9 - y = 8. By subtracting 9 from both sides and multiplying both sides by -1, we can get our value of y, giving y = 1.