Answer:
C. 
Step-by-step explanation:
Alan and his classmates found that the line of best fit through the data had the equation 
The slope of this line is 
If a line would intersect this line of best fit at right angles, then the two lines are perpendicular to each other.
The slopes of perpendicular lines are negative reciprocals of each other,
Hence that line must have slope 
Therefore we look for a line whose slope is
from the given options.
That line is the third option 
A) The given equation has no solution. The absolute value cannot be negative, but must be -9 in order for the equation to be satisfied.
b) |x -7| = 2 . . . . . . . the equation
Solution 1:
-2 = x -7
5 = x . . . . . . add 7
Solution 2
x -7 = 2
x = 9 . . . . . . add 7
The two numbers are {5, 9}

is conservative if there is a scalar function
such that
. This would require



(or perhaps the last partial derivative should be 4 to match up with the integral?)
From these equations we find





so
is indeed conservative, and the gradient theorem (a.k.a. fundamental theorem of calculus for line integrals) applies. The value of the line integral depends only the endpoints:


What does the spaces in between the numbers mean