Khan Academy's Algebra 1 course is built to deliver a comprehensive, illuminating, engaging, and Common Core aligned experience! **Teaching this course? Check out our [teacher resources] …

The substitution method is a technique for solving a system of equations. This article reviews the technique with multiple examples and some practice problems for you to try on your own.

Across the globe, 617 million children are missing basic math and reading skills. We’re a nonprofit delivering the education they need, and we need your help.

Learn fifth grade math—arithmetic with fractions and decimals, volume, unit conversion, graphing points, and more. This course is aligned with Common Core standards.

When solving a system of equations using substitution, you can isolate one variable and substitute it with an expression from another equation. This will allow you to solve for one …

Learn eighth grade math—functions, linear equations, geometric transformations, and more. (aligned with Common Core standards)

This top one, you still didn't mess up by just setting u equal to sine of 5x, we just have to do an extra substitution in order to work it through all the way. And I was able to do this video despite …

Learn to solve the system of equations -3x - 4y = -2 and y = 2x - 5 using substitution.

Learn to solve the system of equations y = -1/4x + 100 and y = -1/4x + 120 using substitution. Created by Sal Khan and Monterey Institute for Technology and Education.

If one line is useful, let's see what we can do with two lines. In this unit, we learn how to write systems of equations, solve those systems, and interpret what those solutions mean in a real …