Answer: 20
Step-by-step explanation: 5 times 4 is 20 times 2 is 40, but when you divide by 1/2 you drop down to 20.
Y-intercept (7,0) x-intercept (0,14) = f(x)= -2x+14
Indirect material cost: y
explained by units produced: x
Linear regression. Cost estimation equation: y=mx+b
Constant: b=$15,640
Standard error of y estimate=$3,600
r^2=0.7704
Number of observations: n=22
x coeffient: m=11.25
Standard error of x coefficient=2.19
m=11.25, b=15,640 → y=11.25x+15,640
Answer: The cost estimation equation is y=11.25x+15,640
Usually one will differentiate the function to find the minimum/maximum point, but in this case differentiating yields:

which contains multiple solution if one tries to solve for x when the differentiated form is 0.
I would, though, venture a guess that the minimum value would be (approaching) 5, since the function would be undefined in the vicinity.
If, however, the function is

Then differentiating and equating to 0 yields:

which gives:

or

We reject x=5 as it is when it ix the maximum and thus,

, for