An item costs $320 before tax, and the sales tax is $12.80. Find the sales tax rate. Write your answer as a percentage

4%

Step-by-step explanation:

As, some rate of $320 will give u 12.80

Now to find the percentage u always use this procedure :

Sales tax value = 12.80 divided by the the total cost ( $320) multipled by hundred

So 12.80/320 x 100 = 4

So 4%

This method help me alot in my solving skills

And used it everytime a question like this is given

So I hope u use it for such questions and u will get right with all hope!

Hope this helps!!

since your problem is x^4 = 81, what you have to undeo is the "to the fourth power" part.

the inverse (opposite operation) of "to the fourth power" is "to the fourth root".

  (x^4) ^ ¼   = 81 ^ ¼  

  81 = 3^4     so (3 ^ 4) ^ ¼   =   3 ^ 1   = 3

by hand: (3 ^ 4) ^ ¼   =   3 ^ (4 x ¼) = 3 ^ 1   = 3   (when you take a power to a power, multiply the exponents.)

or, do it by calculator. one way of finding the fourth root is to use ^ (1/4)

step-by-step explanation:

answer: x=60