Help please

1. Function

2. Not a function

3. Not a function

4. Function

Step-by-step explanation:

All functions must not have a repeated x-value, because they have to pass the vertical line test. Hope this helps!

+25 = x

step-by-step explanation:

here x is the hypotenuse of a right triangle whose legs are 7 and 24.   by the pythagorean theorem, 7² + 24² must equal x²:

x² = 49 + 576 = 625.   thus, x = +√625 = +25 = x