For Exercises 13-14, use the following information. At a store, the daily number
of sales, y, is approximately related to the number of employees, x, by the equation
y= 50 + 10 sqrt x+5.
13. Determine the approximate number of sales if there are 12 employees. Round to the
nearest whole number.

for finding the midpoint of any given 2 pair of points simply add the respective x coordinates with other x coordinate and the y coordinate with other y coordinate and divide them by 2

in your question it will be :

(3+1)/2 for the x coordinate of mid point i.e 2

[8+(-4)]/2 for the y coordinate of midpoint i.e 2

so coordinates of mid point of points (3,8) and (1,-4) will be (2,2)

80x^8−68x^6+16^5−20x^4−4x^3+8x^2

hope i'm right lol