Answer:
Step-by-step explanation:
tax = 7% of $45.09 = 0.07×$45.09 ≅ $3.16
Total cost = $45.09 + $3.16 = $48.25
y/x = k
6.4/4 = 1.6
11.2 / 7 =1.6
16/10 = 1.6
20.8 /13 =1.6
This is a direct variation and the constant is 1.6
y=1.6x
So we have the system of equations:

equation (1)

equation (2)
To use substitution, we are going to solve for one variable in one of our equations, and then we are going to replace that value in the other equation:
Solving for

in equation (2):



equation (3)
Replacing equation (3) in equation (1):






equation (4)
Replacing equation (4) in equation (3):



We can conclude that the solution of our system of equations is <span>
(7/5, 21/10)</span>
You got 21 papers on Monday. Because if you add 3 7 times it equals 21.
Hope it is correct!
All I know is the first one is -0.8 ft/min