Find rule for g^-1(x) if: g(x)=4-5x

Jonathan puts $400 in a bank account. each year the account earns 6% simple interest. how much interest will be earned in 5 years?

The length of the line segment ac is 8x-9 what is the value of x

Akayaker travels 3 miles upstream and 3 miles downstream in a total of 4 hours. in still water, the kayaker travels at a speed of 2 mph. what is the average speed of the river's current?