If you're seeing this message, it means we're having trouble loading external resources on our website.

If you're behind a web filter, please make sure that the domains *.kastatic.org and *.kasandbox.org are unblocked.

Main content

One-step equations intuition

In this math lesson, we learn how to solve a balance scale problem with unknown mass. We represent the problem using an algebraic equation, 3x = 9, where x is the unknown mass. By dividing both sides by 3, we find that x = 3, meaning each object has a mass of 3 kilograms. Created by Sal Khan.

Video transcript