Answer:
sorry, I think yr question is incomplete.
I am guessing your problem should read...
A) n = -5n + 90 (isolate the variables by adding 5n to each side)
+5n +5n
6n = 90 (since we don't want to know what 6n's are worth, divide by 6)
6n/6 = 90/6
n = 15
I think that it is 15 minutes
Since you are solving for x, you need to isolate x on one side of the equation. Start by subtracting C from both sides.
0 = x + a / b - C
Subtract x from both sides to have it on the left side of the equation.
-x = a / b - C
Make x a positive number by dividing both sides by negative one.
x = - a / b + C
A better way of writing this answer would be:
.