SOLUTION: {(1,-1),(0,0),(3,-3),(-2,2)} is this relation a function? Why?

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Question 662037: {(1,-1),(0,0),(3,-3),(-2,2)} is this relation a function? Why?
Answer by MathLover1(20849) About Me  (Show Source):
You can put this solution on YOUR website!
{(1,-1),(0,0),(3,-3),(-2,2)}
There are 2 ways to check this.
1. make a graph and plot out all the coordinates, and if one point is on exactly on top of another, it is not a function
If it isn't, then it is a function (it's vertical line test)
2.
look at all the x's (1st number) and see if any are the same:
we have 1,0. 3,and -2- none of them repeat so this is automatically a function

now lets look at the inverse

since our y's become x's, lets look at the y's in the original function: we have -1, 0, -3, and 2
none of them repeat
however, it the two points had the same y's, it would still be a function

here is a graph;


Solved by pluggable solver: FIND EQUATION of straight line given 2 points
hahaWe are trying to find equation of form y=ax+b, where a is slope, and b is intercept, which passes through points (x1, y1) = (1, -1) and (x2, y2) = (3, -3).
Slope a is a+=+%28y%5B2%5D-y%5B1%5D%29%2F%28x%5B2%5D-x%5B1%5D%29+=+%28-3--1%29%2F%283-1%29+=+-1.
Intercept is found from equation a%2Ax%5B1%5D%2Bb+=+y%5B1%5D, or -1%2A1+%2Bb+=+0. From that,
intercept b is b=y%5B1%5D-a%2Ax%5B1%5D, or b=-1--1%2A1+=+0.

y=(-1)x + (0)

Your graph: