algebra
posted by katie .
what is 4p+3q=36
9p+6q=78 ?

4p+3q=36 (1)
9p+6q=78 (2)
You want to eliminate either the p's or q's to solve for one. Eliminating the q's is easier because you only have to change one equation. Multiplying (1) by 2...
8p6q=72 (3)
9p+6q=78 (2)
Add the equations together.
p=6
Now substitute p=6 in either equation 1 or 2 to figure out what q equals.