For this case we have that by definition, the equation of the line of the slope-intersection form is given by:

Where:
m: It is the slope of the line
b: It is the cut-off point with the y axis.
According to the data of the statement we have the following points:

We found the slope:

Thus, the equation is of the form:

We substitute one of the points and find b:

Finally, the equation is:

Answer:

If There is a math equation you can use math-way.
Also it would help if you can take a better picture.
Once you take a better picture I promise i will try my best to answer the question.
Answer: 6247.5
Step-by-step explanation:
85% x 105000 = 89250
70 x 89.25 = 6247.5