40 miles an hour and yeah..
We'll first simplify both sides of the expression to get (simply using the distributive property):

Then, we can simplify a little bit:

To solve for n, we have to isolate it. Let's subtract 3n from both sides to further simplify it:

Then, add 18 to both sides to get the value of n:

And that's your answer. If you have questions on how I got that, feel free to ask!
Answer:
m+n=9
Step-by-step explanation:
Put the equation into the form ka^mb^n by multiplying the coefficients (-1*2*-3), so k= 6, then add the exponents of a together, a^2+a^1= a^3, m=3.
Now you have 6a^3, next we do the exponents of b together, b^3, b^2, b^1= b^6, n=6.
This is 6a^3b^6. m=3 and b=6, so add m+n=9.
Answer: Brand B is the best unit price
Explanation:
Brand A:
6 = 54$
1 = 54/6
1 = 9$
Brand B:
9 = 63$
1 = 63/9
1 = 7
So brand B is much cheaper