Lesson 6: Two-Step Equations
Most real-world equations take two steps to solve. The strategy: undo addition/subtraction first, then undo multiplication/division. Work in reverse order of operations.
Key Concepts
Two-Step Strategy
2x + 3 = 11. Step 1: subtract 3 from both sides → 2x = 8. Step 2: divide both sides by 2 → x = 4. Always undo + or - before × or ÷.
Negative Coefficients
−4x + 6 = −10. Step 1: subtract 6 → −4x = −16. Step 2: divide by −4 → x = 4. Dividing by a negative flips the value but not the equals sign here.
Fraction Coefficients
(x/3) + 7 = 13. Step 1: subtract 7 → x/3 = 6. Step 2: multiply by 3 → x = 18. OR multiply through by 3 first to clear the fraction.
Word Problems
Maya has $3 more than twice what Carlos has. Maya has $17. How much does Carlos have? Let c = Carlos's amount. 2c + 3 = 17. 2c = 14. c = $7.
🔬 Interactive Lab: Two-Step Equations Lab
✅ Check Your Understanding
1. To solve 3x - 7 = 14, what is the FIRST step?
2. Solve: 2x + 5 = 17
3. Solve: -3x + 9 = 0