How to figure out general formula for partial sums.

Consider the function y = f(x)=3^x the values of f(1/2) and f(1/4). rounded to the nearest hundredth, are__and__ respectively

You are at a restaurant and owe $38 for your meal. you want to leave a 20% tip. how much will your tip be?

In dire need~! describe how to use area models to find the quotient 2/3 divided by 1/5. check your work by also finding the quotient 2/3 divided by 1/5 using numerical operations only.