➕ 8th Grade Math · Unit 3

Linear Equations

12 short narrated lessons in 2 chapters, each with pictures, a quiz with a hint and a second try, and an explanation for every answer.

Standards: 8.EE.C.7 8.EE.B.5 8.EE.B.6

8th Grade Math · 8 units

Picture from the lesson “Variables on both sides” — Variables on both sides

Picture from the lesson “Equations with parentheses” — Equations with parentheses

Picture from the lesson “Equations with fractions and decimals” — Equations with fractions and decimals

What your child will learn

Solving linear equations

Variables on both sidesSolve equations like five x minus three equals two x plus nine by collecting variables on one side.
Equations with parenthesesSolve equations that need the distributive property and combining like terms.
Equations with fractions and decimalsSolve linear equations with fraction and decimal coefficients.
One, none or infinitely many solutionsTell whether a linear equation has one solution, no solution or infinitely many solutions.
Solving linear equations review ReviewReview solving multi-step linear equations and deciding how many solutions they have.

Slope and proportional relationships

Graphing Proportional RelationshipsGraph a proportional relationship and read the unit rate as the slope.
Comparing Proportional RelationshipsCompare two proportional relationships shown in different ways, like a graph and an equation.
Finding SlopeFind the slope of a line as rise over run using two points.
Slope and Similar TrianglesUse similar triangles to explain why slope is the same between any two points on a line.
Where y = mx + b Comes FromExplain where the equations y equals m x and y equals m x plus b come from.
Slope and Proportional Relationships Review ReviewReview graphing proportional relationships, slope, similar triangles and y equals m x plus b.
Unit 3 Test: Linear EquationsShow what you learned in the whole unit (Solving linear equations, Slope and proportional relationships) by answering mixed questions.

Try a question from this unit

From the lesson “Variables on both sides”

Solve 6x + 4 = 2x + 24.

x = 7
x = 2.5
x = 5
x = 20

Show the answer

x = 5. Subtracting 2x from both sides gives 4x + 4 = 24, then 4x = 20, so x = 5. The answer 2.5 comes from adding 2x to the left instead of subtracting it from both sides.

Hint kids see after a wrong try: “Which variable term is smaller? Remove it from both sides first, then deal with the plain numbers.”

Key words

variable
linear equation
distributive property
like terms
coefficient
no solution
infinitely many solutions
unit rate
slope
compare
rise
run
similar triangles
y-intercept
slope-intercept form

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Narrated lessons, pictures and quizzes for every grade from K to 8. Works offline.