Answer: 6
Step-by-step explanation:
Slope is found by doing:

(x1 and y1 must be from the same ordered pair and x and y must be from the same ordered pair, however point (x1,y1) and (x,y) can be used interchangeably)
Let us say that (x1,y1) is (3,18)
And (x,y) is (5,30)

They can not, there are only 2 sides and they probably flipped it different ways. They got 'lucky'.
Answer: You're answer is 7.
Step-by-step explanation: 2+2=4+4=8-1=7