Question

I dont understand this please help

Answer 1

C.

Explanation:

If a vertical line is moved across the graph and, at any time, touches the graph at only one point, then the graph is a function. If the vertical line touches the graph at more than one point, then the graph is not a function.

The vertical parabola is the only graph here that will only touch the graph at one point, so it is the only function.

Answer 2

Answer: C

Explanation:

Every x value can only have one specific y value. You will have to perform the vertical line test. Basically grab a ruler and slide it across your graphs vertically ( drag the ruler upright from left to right). Look at your x intercepts and their specific y intercepts.

For A, it continously crosses over so it is not a function. For B, it is always crossing over 2 times so it is not a function. For C, every x intercept has a specific y value therefore it is a function. It crosses over at one point only. For D, the vertical is always crossing over 2 times therefore it will not be a function.