Please help me on this.

first one: function

second one: not a function

third one: not a function

fourth one: not a function

Step-by-step explanation:

it is never a function if two of the x inputs are the same or if one x input has two y outputs..

Hope this helps

step-by-step explanation:

use pothagarean therom

a^2+b^2=c^2 so first ac

acm is a right triangle because c= 90°

and am (the hypotenuse or c) =16+9 =25

but there is not enough info we need another angle or side length