Answer:
A. 
Step-by-step explanation:
The equation in slope-intercept form,
, can be created to be used in finding Jack's pay. We need to find the slope (m) and the y-intercept (b) of the linear function.
Using two points (1, 18), and (1.5, 23), find the slope (m):
Slope (m) = 
Find b, by substituting x = 1, f(x) = 18, and m = 10 into
.


Subtract 10 from each side



Substitute m = 10 and b = 8 into
.
✅Thus, the linear function that can be used to find Jack's pay would be:

To buy 3 books Kaitlyn will need $27
Sum/Difference of 2 monomials is (in simplest terms) a monomial when the 2 monomials are 'like terms
3y - y + 8 - 2 = 20
3y - y = 2y
8 - 2 = 6
2y + 6 = 20
2y = 20 - 6
y = 10 - 3
the answer is: y = 7