7th Grade Substitution Worksheet — Level 3 — Practice Set 2 — Answers
Answer sheet with worked solutions for the 7th Grade algebraic expressions worksheet.
Success TutoringWorksheetsAnswer sheet7th Grade · Mathematics · Algebraic Expressions7th Grade Substitution Worksheet — Level 3 — Practice Set 2 — Answers
Replace the letter with the number, then calculate. Use parentheses for negative values.
1.If x = 1 and y = −3, find the value of 3x2 − 2y
Answer: 9
- 3 × (1)² − 2 × (−3)
- = 3 + 6 = 9
2.Find the value of −2x − 8 when x = 7
Answer: −22
- −2 × 7 − 8
- = −14 − 8 = −22
3.If x = −4 and y = −5, find the value of 9x2 − 2y
Answer: 154
- 9 × (−4)² − 2 × (−5)
- = 144 + 10 = 154
4.Find the value of −2x + 1 when x = 8
Answer: −15
- −2 × 8 + 1
- = −16 + 1 = −15
5.If x = 1 and y = 1, find the value of 2x2 − 4y
Answer: −2
- 2 × (1)² − 4 × (1)
- = 2 − 4 = −2
6.If x = 2 and y = 5, find the value of 2x2 + 7y
Answer: 43
- 2 × (2)² + 7 × (5)
- = 8 + 35 = 43
7.If x = 8 and y = −5, find the value of 3x2 − 2y
Answer: 202
- 3 × (8)² − 2 × (−5)
- = 192 + 10 = 202
8.If x = −4 and y = 1, find the value of 3x2 − y
Answer: 47
- 3 × (−4)² − 1 × (1)
- = 48 − 1 = 47
9.Find the value of −x + 6 when x = 1
Answer: 5
- −1 × 1 + 6
- = −1 + 6 = 5
10.If x = 4 and y = −4, find the value of 5x2 − y
Answer: 84
- 5 × (4)² − 1 × (−4)
- = 80 + 4 = 84
11.Find the value of x − 2 when x = −4
Answer: −6
- 1 × (−4) − 2
- = −4 − 2 = −6
12.If x = −2 and y = 1, find the value of −x2 + 3y
Answer: −1
- −1 × (−2)² + 3 × (1)
- = −4 + 3 = −1
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.