How do u write a equation for 15x-3y=15 in slope intercept form?

15x-3y=15
-3y=-15x+15
y=5x-5

In words:
1. Subtract 15x from both sides so that the y is by itself
2. Divide everything by -3 so that the y has no coefficient

Since we are looking for the principal amount, then all we have to do is reverse the process of getting the amount of tax. In order to get the principal, you just have to divide 22 with 0.05. The answer is 440 so that is the principal amount you are looking for.