Solve the simultaneous equations: 3x+2y=22, x=y-1

We can see that x=y-1 and therefore can sub this in our first equation, to give us 3(y-1)+2y=22. If we expand the brackets we than have 3y-3+2y=22 which can be tidied up to give 5y-3=22. If we add 3 to both sides this gives us 5y=25, and dividing both sides by 5 gives us y=5. If we then sub y=5 into the second equation, x=5-1, we find that x=4.