Worked examples
Two examples
Example 1
Solve: 3x + 5 = 20
- Step 1, undo the adding: 3x = 20 − 5 = 15.
- Step 2, divide by 3: x = 5. Check: 3 × 5 + 5 = 20.
Answer: x = 5
Example 2
Solve: −2x + 7 = −5
- Undo the adding: −2x = −12.
- Divide by −2: x = 6.
Answer: x = 6
Where this is taught: Algebra Practice 1, “15. Two steps”
The drill
Ten problems
How many:
Type each answer, then press Check my answers at the bottom. Commas in large numbers are fine.Write each answer on the line. The answer key, with the reasoning, is on the last page.