In this type of calculations, we decompose 13 by checking the lowest powers of the base, that is 40. for example we check 40^2, or 40^3 and compare it to 85
Notice
40*40*40=64,000
so we check how many time does 85 fit into 64,000:
64,000/85=752.94
85*753=64,005; 64000-64,005=-5
this means that

thus

Answer: 10 (mod85)
Remark, the set of all solutions is:
{......-75, 10, 95, .....}, that is 85k +10
Answer:
C = 40 + 0.17M
Step-by-step explanation:
Total monthly charge = Fixed base fee + charge per minute*total number of minutes
C = 40 + 0.17*M
C = 40 + 0.17M
By synthetic division, the quotient (4x^2 -10x -24)/(2x +3) is 2x -8.
___
You have not actually said what division you want performed.
A person sold 100 shares of a stock at a loss of 40%.
selling price for the 100 shares was $3,000
Let the stock was bought at $x then we can write

Hence Amount paid for the Stock was $5000