Question

If 7p + 5q = 2 and 8p - 9q = 17, then -p + 14q =

Answer 1

I would use substitution to first solve for p and q in the first 2 equations. Then you can plug those in to solve for equation 3

Answer 2

Using the two equations, find the value of p and q individually and then find the value of -p + 14q.
7p + 5q = 2
7p = 2 - 5q
p = (2 - 5q)/7
Substitute this in the second equation to get the value of q, then find p.