Help On An Algebra Problem

We can equate slopes to find p

[ -14 - -5 ] / [ p  - 2 ]    =  [ -17 -  - 5 ] / [p + 2 - 2]

[ -9] / [ p - 2] =   [ -12 ] / p         cross-multiply

-9p  = [ -12 ] [ p  - 2 ]   simplify

-9p = -12p + 24       add 12p to both sides

3p = 24       divide both sides by 3

p = 8

So....the slope   is       (-12) / (8) =  -3/2

And the equation of the line is

y = (-3/2)(x - 2) - 5

y = (-3/2)x + 3 - 5

y = (-3/2)x - 2

So....when x = 13

q = (-3/2)(13) - 2    =  (-39/2) - 2 =  -43/2  =  - 21.5

So

p + q =

8 + (-21.5)  =

-13.5