Which equation is a function of x? a. x=5 b. x=y2+9 c. x2=y d. x2=y2+16

A function is a process or a relation that associates each element x of a set X  to a single element y of another set Y.

A. The equation represents vertical line. This is not a function, because one element x=5 is associated to all (not one) elements of

B. The equation represents parabola that goes in positive x-direction. This is not a function, because each is associated to two different y. For examlpe, when x=10, then

C. The equation represents parabola that goes in positive y-direction. This is the function, because for each x is associated only one y.

D. The equation represents hyperbola. This is not a function, because for one x there are two different possible y.

correct choice is C

c ; Since -2 is rational and square 3 is irrational, the sum and difference are irrational.

Step-by-step explanation: Just took the test