Expert: Scott A Wilson - 9/3/2010

Question
9 – 6g= f
-6g + 3f=15


Answer
Take f = 9 - 6g and put that into the 2nd equation.
Since it is a 3f in the 2nd equation, that would be 3(9-6g) = 27-18g.
Thus, the 2nd equation becomes -6g + 27 - 18g = 15.

The g's combine to -24g.  Subtracting 27 from both sides gives 0 on the left and -12 on the right.  Thus, we have -24g = -12.
Divide both sides by -24 to get a value for g.

Put this back into the 1st equation to get a value for f.

Put this back into the 2nd equation to check and make sure the same value is gotten for f.