You can see 84.78 as
.
So, you can see the problem as 
First, multiply all the numerators together and all the denominators together.
You end up with 
=33.912
I'd do 9x4=36 because the 9 is from your money and the 4 is from your books. Now since you want to find out how much 4 books cost you just multiply that by 9
Using the given linear function of best-fit, the most likely approximate height of the plant after 8 weeks would be of 7.4 centimeters.
<h3>What is a linear function?</h3>
A linear function is modeled by:
y = mx + b
In which:
- m is the slope, which is the rate of change, that is, by how much y changes when x changes by 1.
- b is the y-intercept, which is the value of y when x = 0, and can also be interpreted as the initial value of the function.
The line of best-fit goes through points (0,1) and (5,5). Point (0,1) means that the y-intercept is of b = 1. The slope is given as follows:
m = (5 - 1)/(5 - 0) = 4/5 = 0.8.
Hence the equation that gives the approximate height after x weeks is:
y = 0.8x + 1.
After 8 weeks, the expected height is:
y = 0.8 x 8 + 1 = 6.4 + 1 = 7.4 centimeters.
More can be learned about linear functions at brainly.com/question/24808124
#SPJ1