Which rule describes the relationship between x- and y- coordinate on the following graph

What is the name used to describe a graph where for some value of x, there exists 2 or more different values of y?

How many kilograms of a 5% salt solution and how many kilograms of a 15% salt solution must be mixed together to make 45kg of an 8% salt solution?

Look at triangle wxy what is the length (in centimeters) of the side wy of the triangle?