Question

For each function determine if the given function is on the graph. y = 7x-2; (1,5) and (2,10)

Answer 1

We have here a function y=f(x)=7x-2
We can check (1,5), and x=1, y=5 and we have 5=7x1-2, that is right.
But (2,10) we can see x=2, y=10 and 10=7x2-2 or 10=12, that is wrong.

Answer 2

To do this, find the equation that would connect the two points...

First, find the slope between the two points
slope = m = (y1 - y2) / (x1 - x2) = (5 - 10) / (1 - 2) = -5/ -1 = 5

Since the slope between the two points is 5 and not 7, the points will no be on the line.

P.S. Hope this helps :)