Answer:
x = 7
Step-by-step explanation:

Given that the method of revenue calculation is straight line method, the equation modeling this will be given by:
y=mx+c
where:
m=slope
x=time
c=initial value.
from our question:
slope,m=$7000
time=T
y(x)=R(t)
hence the formula after the sixth month will be:
R(t)=7000T+45000
The answer for part b is 6
Answer:
Interest= $ 18.73
Step-by-step explanation:
Given : $600 at 9.5% for 120 days
To find : Find the interest due
Solution :
Simple interest formula 
Principle(P)=$600 , rate(r)=9.5%=0.095 , time (t)= 120 days
In years, 1 year = 365 days
1 day =
year
120 days =
year
Put values in the formula


Therefore, Interest= $ 18.73