2t-2/t^2-1 simplify the expression

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

Someone this asap for a group of students attends a basketball game. * the group buys x hot dogs at the concession stand for $2 each. * the group buys y drinks at the concession stand for $3 each. the group buys 29 items at the concession stand for a total of $70. how many hot dogs did the group buy?

Show your workcan a right triangle have this sides? *how to prove it without using the pythagorean theorema*