Like what you saw?
Create FREE Account and:
 Watch all FREE content in 21 subjects(388 videos for 23 hours)
 FREE advice on how to get better grades at school from an expert
 Attend and watch FREE live webinar on useful topics
Solving Exponential Equations with the Different Bases  Problem 1
Carl Horowitz
Carl Horowitz
University of Michigan
Runs his own tutoring company
Carl taught upperlevel math in several schools and currently runs his own tutoring company. He bets that no one can beat his love for intensive outdoor activities!
Solving a exponential equation when we can’t rewrite our bases as the same base. What we have here is 5 to a power is equal to 13. The first thing we have to, first you noticed that 5 and 13 can’t be written as the same base. What we first have to do is figure out a way to bring down this t. We’re solving for t so we need to somehow get it down to the level we know how to manipulate it. In order to do that we have to take the log of both sides. It doesn’t’ matter what base you’re using as long as the base is the same.
So for this example I’m just going to use the common log, log base 10, so we take the log of both sides. Once we take the log of both sides we now have an exponent which we can bring down in front using our power rule. What we end up with is –t plus 1 log of 5 equals log of 13. Now we just want to solve for t.
Log of 5 and log of 13 are ugly numbers, we don’t know what they are but they’re still just numbers, so we can deal with them just as we would anything else. We want to solve for –t. There’s number of different ways of dong that, we could distribute the log 5 into here, we could divide by log 5, doesn’t really matter, just a different couple of different options we're going to do.
I am going to divide by log 5. What we end up with then is t plus 1 is equal to log 13 over log 5. Subtract 1, t is equal to log 13 over log 5 minus 1 and then in order to get the t by itself we need to divide by 1, so we make the logs negative and the 1 positive.
Finishing up we end up with t is equal to negative log 13 over log 5 and then divide by 1, so that just turns into a positive 1. Taking the log of both sides in order to solve an exponential equation.
Please enter your name.
Are you sure you want to delete this comment?
Carl Horowitz
B.S. in Mathematics University of Michigan
He knows how to make difficult math concepts easy for everyone to understand. He speaks at a steady pace and his stepbystep explanations are easy to follow.
i love you you are the best, ive spent 3 hours trying to understand probability and this is making sense now finally”
BRIGHTSTORM IS A REVOLUTION !!!”
because of you i ve got a 100/100 in my test thanks”
Sample Problems (8)
Need help with a problem?
Watch expert teachers solve similar problems.

Solving Exponential Equations with the Different Bases
Problem 1 15,826 viewsSolve:
5^{t + 1} = 13 
Solving Exponential Equations with the Different Bases
Problem 2 10,571 viewsSolve:
e^{0.04x} = 18 
Solving Exponential Equations with the Different Bases
Problem 3 9,497 viewsSolve:
10^{x + 1} = 8 
Solving Exponential Equations with the Different Bases
Problem 4 11,125 viewsSolve:
7^{x + 1} = 9^{x − 4} 
Solving Exponential Equations with the Different Bases
Problem 5 2,215 views 
Solving Exponential Equations with the Different Bases
Problem 6 1,776 views 
Solving Exponential Equations with the Different Bases
Problem 7 1,899 views 
Solving Exponential Equations with the Different Bases
Problem 8 1,906 views
Comments (0)
Please Sign in or Sign up to add your comment.
·
Delete