How Do You Solve a Word Problem Using an Equation With Variables on Both Sides? Please give an math example

Which of the following graphs represents the function f(x) = 2^x

Orly uses 2 cups of raisins for every 12 cups of trail mix she makes. how many cups of trail mix will she make if she uses 8 cups of raisins?

On a string instrument, the length of a string varies inversely as the frequency of its vibrations. an 11-inch string has a frequency of 400 cylces per second. find the frequency of a 10-icnch string.