Year 8 Substitution Worksheet — Level 1 — Practice Set 3 — Answers
Answer sheet with worked solutions for the Year 8 algebraic expressions worksheet.
Success TutoringWorksheetsAnswer sheetYear 8 · Mathematics · Algebraic ExpressionsYear 8 Substitution Worksheet — Level 1 — Practice Set 3 — Answers
Replace the letter with the number, then calculate. Use brackets for negative values.
1.Find the value of x − 9 when x = 5
Answer: −4
- 1 × 5 − 9
- = 5 − 9 = −4
2.Find the value of 9x + 6 when x = 4
Answer: 42
- 9 × 4 + 6
- = 36 + 6 = 42
3.Find the value of 9x − 3 when x = 4
Answer: 33
- 9 × 4 − 3
- = 36 − 3 = 33
4.Find the value of 6x + 6 when x = 9
Answer: 60
- 6 × 9 + 6
- = 54 + 6 = 60
5.Find the value of −4x when x = 3
Answer: −12
- −4 × 3 + 0
- = −12 + 0 = −12
6.Find the value of −5x + 6 when x = 4
Answer: −14
- −5 × 4 + 6
- = −20 + 6 = −14
7.Find the value of 2x − 2 when x = 7
Answer: 12
- 2 × 7 − 2
- = 14 − 2 = 12
8.Find the value of 9x − 7 when x = 8
Answer: 65
- 9 × 8 − 7
- = 72 − 7 = 65
9.Find the value of −2x − 4 when x = 2
Answer: −8
- −2 × 2 − 4
- = −4 − 4 = −8
10.Find the value of 2x + 8 when x = 3
Answer: 14
- 2 × 3 + 8
- = 6 + 8 = 14
11.Find the value of 9x + 5 when x = 6
Answer: 59
- 9 × 6 + 5
- = 54 + 5 = 59
12.Find the value of x − 5 when x = 8
Answer: 3
- 1 × 8 − 5
- = 8 − 5 = 3
Marking tips
- Give credit for correct method even when the final answer slips — the working shows where the thinking went right.
- For open-ended tasks, use the success criteria as a checklist rather than looking for one "right" answer.
- Celebrate what went well first, then pick one thing to work on next.