SIMULTANEOUS EQUATIONS

TIP: When doing these sort of problems, remember:

a) As ever be careful when dealing with negative numbers, remember that e.g. 2 - -3 does not = -1, but 5 !.

b) Always look for the easiest way to combine the two equations e.g.

2x - 4y = 6        (1)
4x +2y = 22      (2)

It's easiest to multiply equation (1) by -2 to give -4x + 8y = -12, then adding the two equations will cancel the x's and leave you with 10y = 10 (no prizes for getting the answer to this one!).

c) Always remember to do the same thing to the right of the equation as you do to the left e.g. if you multiply 2x - 4y = 6 by -2, this gives (-2 multiplied by 2x) + (-2 multiplied by -4) = (-2 multiplied by 6).

d) If you're not totally confident that you've got it right, substitute your calculated values for x and y (or a and b etc.) back into both equations.

Solve the following simultaneous equations.