Do you mean 5+7?
If so, that equals 12!
First find out the function for the given table.
Find the slope.
m= (y2-y1)/(x2-x1)
m=(-1-(-3)) / (-1-(-2))
m=(-1+3) / (-1+2)
m=2/1
m=2
Now equation of line:
y-y1=m(x-x1)
y-(-3)=2(x-(-2))
y+3=2(x+2)
y+3=2x+4
y=2x+1
Now plot these points on the graph, we get the attached graph.
24x-36 . because you distribute the six to simplify your answer. <span />
Answer:
Modification has not reduced the number of accidents.
Step-by-step explanation:

A B C D E F G H
Before modification 5 7 6 4 8 9 8 10
After modification 3 7 7 0 4 6 8 2
Difference -2 0 1 -4 -4 -3 0 -8
Mean of differences 
Standard deviation of differences = 
Formula of paired t test :

Df = n-1 = 8-1 =7

t critical> t calculated
So, We failed to reject null hypothesis
Hence modification has not reduced the number of accidents.
I have included the answer and work in the picture attached below (the side length for the bottom leg is cut off, but it is 16 sqrt(2)):