Answer:
12) s=
13) A=wh
14) p=a+b+c
15) A=
16) p-b-c=a
Step-by-step explanation:
12) 
13)
=W (multiply both sides by h)
14) take c to the other side of the equation( other side of the equal sign) it becomes a positive value
15) Divide both sides by 2
16) take b + c to the other side of the equation where it becomes -b-c
A vertical line has the equation of x = a
If the vertical line goes through a certain point, as in this case, then the y value is irrelevant. It can be anything. It is the x value that is the one you need to use.
So the answer is x = 1. This equation has no slope that is defined.