We have two equation with two unknowns. Therefore, we can solve the x and y easily. There are a number of methods to apply here but I will be using substitution method. We do as follows:
-2x + y = 1
y = 1 + 2x
4x + y = -1
4x + 1 + 2x = -1
6x = -1 -1
6x = -2
x = -1/3
y= 1 + 2(-1/3)
y = 1/3
Is this a relation: {(-2,1), (0,0), (0,1), (1,-2), (1,0), (1,3), (2,0)}? Explain why or why not.
tatiyna
It is a relation because any relation is simply a set of (x,y) values known as points or ordered pairs. There are no other qualifications needed to be a relation. We simply pair up any x and y value we want.
I think you meant to ask if it's a function or not. If so, then the answer is "no, it is not a function". Why not? Because the x value x = 0 produces more than one y output y = 1 and y = -2. Graph these points and you'll see them fail the vertical line test (ie its possible to draw a vertical line through more than one point on the graph). The same issue happens with (1,-2), (1,0) and (1,3) as well.
In summary:
Yes it is a relation
No it is not a function
The reasoning for each is stated above
Nope - 320 millimetres = 32 centimetres. 3.2 metres is 320 centimetres, which is 3,200 millimetres
