REARRANGEMENT OF FORMULAE

TIP: When doing these sort of problems, remember these things:

a) Whatever you do to one side of a formula, you must also do the same to the other
    side:

     To rearrage the following formula making x the subject (this means you have a formula of form x = something):
      x + 2y = 3x - y

     Add y to both sides of the formula giving:
     x + 2y + y = 3x - y + y

     As (-y + y = 0) we can say:
     x + 2y + y = 3x

     Now subtract x from both sides leaving:
     2y + y = 2x

     As 2y + y = 3y we can say:
     3y = 2x

     So to get x we can now divide both sides by 2 (2 divided by 2 on the x side = 1, and 1 times x = x):
     x = 3y/2

b) When you are dealing with more complicated formulae, try to strip off the outer layers
    first. To make x the subject in the example below:

c) When you want to get rid of something in a formula, remember to do the opposite to
    it. If something is added, subtract the same thing and it magically disappears, if     something is squared, do a square root on it and you get rid of the square.

d) You can manipulate existing numbers and letters on one side of the equation in the     normal way e.g. add them togther or factorise or remove brackets etc.

e) Be careful of negatives e.g. subtracting c from -c gives you -2c!

Solve the following: