I need help on vertical angles

each of the pairs of opposite angles made by two intersecting lines.

Step-by-step explanation:

The angles opposite each other when two lines cross. They are always equal.

In this example a° and b° are vertical angles.

"Vertical" refers to the vertex (where they cross), NOT up/down. They are also called vertically opposite angles.

yes because there is exactly one y value for every x value

for function there can't be more than one value for every x value

guess at question:

a vertical line intersects the graph of g(x,y) = 0 at two points. what conclusion follows about the function f(x) implicitly defined by g(x,f(x)) = 0?

the domain of f(x) cannot include the x coordinate of any such vertical line.

informally, f(x) is not a function, and

g(x,y)=0 cannot be solved for y uniquely.

the relation r = {(x,y) such that g(x,y) = 0} is a function if

for all (a,b) ∊ r and (c,d) ∊ r, a=c implies b=d.

step-by-step explanation: