Answer:
13. A
14. C.
Explanation:
A relation is a function if there is only one y assigned to each x.
That is if you have a set of points, there should be no repeated x value.
So looking at {(0,0),(-2,4),(-2,-4),(-3,7)} this is not a function because you have two x's that are the same. A.
The slope-intercept form of a linear equation is y=mx+b where m is the slope and b is the y-intercept.
The y-intercept is where the graph goes through the y-axis at. It goes through at -1 so b=-1.
The slope is rise/run. So starting from the y-intercept (0,-1) we need to find another point to count the rise & run to... How about (3,1)? That works. You can do the counting if you want. You could also use the slope formula.
To use the slope formula, I just like to line the points up vertically and subtract vertically then put 2nd difference over the 1st difference.
(0,-1)
-(3,1)
--------
-3 -2
So the slope is -2/-3 or just 2/3.
So the equation is y=2/3 x-1
C.