Introduction to systems of equations

9 videos
6 skills
Whether in the real world or a cliche fantasy one, systems of equations are key to solving super-important issues like "the make-up of change in a troll's pocket". This tutorial shows you how to solve systems of equations graphically.

Trolls, tolls, and systems of equations

VIDEO 6:51 minutes
A troll forces us to use algebra to figure out the make-up of his currency. We end up setting up a system of equations

Solving the troll riddle visually

VIDEO 5:41 minutes
Solving the system of equations visually. Now we can save the prince/princess

Solving systems of equations graphically

VIDEO 2:22 minutes
Some practice solving systems graphically (exercises available at http://www.khanacademy.org/math/algebra/systems-of-eq-and-ineq/e/graphing_systems_of_equations )

Solving systems of equations graphically

PRACTICE PROBLEMS
Graph a system of equations in slope-intercept or standard form

King's cupcakes: Solving systems by elimination

VIDEO 9:00 minutes
Using simple elimination to figure out how many cupcakes are eaten by children and adults

How many bags of potato chips do people eat?

VIDEO 9:21 minutes
Using elimination to solve a system of equations

Solving systems of linear equations with elimination example 1

VIDEO 4:18 minutes
Practice solving systems of equations through simple elimination

Solving systems of linear equations with elimination 1

PRACTICE PROBLEMS
Solve systems of equation with one-step elimination (e.g., x-values or y-values cancel each other out).

Systems with elimination practice

VIDEO 5:31 minutes
Example of solving systems of equations with elimination

Solving systems of linear equations with elimination 2

PRACTICE PROBLEMS
Solving systems of equations with elimination.

Talking bird solves systems with substitution

VIDEO 5:21 minutes
Solving systems of equations with substitution.

Solving systems of linear equations with substitution

PRACTICE PROBLEMS
Solve systems of equations using substitution

Solving systems of two linear equations

PRACTICE PROBLEMS
Solve systems of equations with substitution and elimination.

Systems of equations word problems

PRACTICE PROBLEMS
Word problems with systems of equations.