Cogito
Algebra 1 · Chapter 1 · Lesson 2
Multi-Step and Literal Equations
Solving for a letter, whichever letter it is.
10 problems · about 20 minutes · A-REI.A.1, A-REI.B.3, A-CED.A.4
What this lesson teaches
The student solves multi-step linear equations and rearranges formulas for a chosen variable.
- Clear brackets, combine, gather, then undo.
- Rearranging a formula is the same process for a different letter.
- Check in the original equation.
Warm-Up Review
From earlier lessons. Loosen up before the new work.
2 problemsReview — Expressions and Their Structure: 3(4x − 2) expands to 12x − what?
Answer 6
Why 12x − 6.
Review — Expressions and Their Structure: What makes two terms like terms?
Answer The same variable to the same power.
Why Same variable, same power.
Warm Up
Straightforward practice. Get the method working first.
4 problemsSolve 3(x + 4) = x + 20.
Answer 4
Why x = 4.
Where should you check your answer?
Answer In the original equation.
Why Check in the equation you were given.
Solve 4(x − 1) = 2x + 6.
Answer 5
Why 4x − 4 = 2x + 6.
Solve 5x + 3 = 2x + 21.
Answer 6
Why 3x = 18.
Build It Up
The same ideas with more to keep track of.
2 problemsP = 2l + 2w with P = 30 and l = 9. What is w?
Answer 6
Why 30 = 18 + 2w.
Solve x/3 + 2 = 6.
Answer 12
Why x/3 = 4.
Stretch Yourself
Mixed problems. Work out what kind of question it is before you start.
2 problemsThe Equation: Solve 2(x + 3) = 3x − 1.
Answer 7
Why x = 7.
The Formula: A = lw with A = 48 and l = 6. What is w?
Answer 8
Why w = 8.