Where's the figure? I can't exactly solve this question without knowing how the figure looks like. So put a picture of the figure and then I'll try to answer your question. :)
I don't know sorry I tried
Find x and y intercept and plot
set x to zero and find y
set y to zero and find x
tada, 2 points
if x=0, then y=-4
if y=0, then x=-16
we havee the points
(0,-4) and (-16,0)
or
y=-1/4x-4
There is no number I can think of that would make the statement untrue.
The result of this when you subtract 83x from both sides leaves you with P = Q.
Unless you know differently, the equation says that P must equal Q no matter what x is. If there is such a condition, it is not obvious.