Primitevly do it like:
6v-13v-18=-81
- 7v= -63
v=9
P.S Strongly recommend to learn algebra's basics
x=4 would be a vertical line
Answer:
The vertical line test can be used to determine whether a graph represents a function. ... If we can draw any vertical line that intersects a graph more than once, then the graph does not define a function because that x value has more than one output. A function has only one output value for each input value.
3,4,7 just plug the x into the equation
