To solve a literal equation, you need to plug the values that you have in to it.
Take the literal equation d=rt
If you are given the rate, r, and time, t, you can plug them in to the equation and solve for d
For example, say the rate is 5 mph and the time is 2 hours.
Put the two in and get d = 5*2, or d = 10.
The unit will depend on what you're solving for, but in this case the the answer is 10 miles.