## x1xofxaxkndx 2 years ago Which of these equations represent functions? Check all that apply. A. y = x2 B. y = 3x C. x2 - y2 = 1 D. y2 = x2

1. x1xofxaxkndx

i think a and c

2. mathstudent55

a & b

3. x1xofxaxkndx

thanks loli got 1 right

4. mathstudent55

c & d are not functions.

5. x1xofxaxkndx

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6. mathstudent55

yes

7. mathstudent55

@ankolix A function is a realtion that maps each element of its domain to a single element of its range. A parabola that opens up or down is a function. A parabola that opens right or left is not a function.

8. mathstudent55

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9. mathstudent55

An easy way to tell if a relation is a function from a graph is the vertical line test. Think of a vertical line moving from left to right on the graph. If in any position, the vertical line intersects more than one point of the relation, then the relation is not a function.

10. x1xofxaxkndx

thanks sooooooo much for the help!!!!!!!!!!

11. mathstudent55

You're very welcome.