Year 8 Substitution Worksheet — Level 3 — 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 3 — Practice Set 3 — Answers
Replace the letter with the number, then calculate. Use brackets for negative values.
1.Find the value of 4x + 3 when x = 5
Answer: 23
- 4 × 5 + 3
- = 20 + 3 = 23
2.If x = −1 and y = 1, find the value of 5x2 + 7y
Answer: 12
- 5 × (−1)² + 7 × (1)
- = 5 + 7 = 12
3.If x = −2 and y = 2, find the value of 9x2 − 7y
Answer: 22
- 9 × (−2)² − 7 × (2)
- = 36 − 14 = 22
4.Find the value of −x + 7 when x = −4
Answer: 11
- −1 × (−4) + 7
- = 4 + 7 = 11
5.If x = −4 and y = −3, find the value of −2x2 + 8y
Answer: −56
- −2 × (−4)² + 8 × (−3)
- = −32 − 24 = −56
6.Find the value of 9x − 7 when x = 3
Answer: 20
- 9 × 3 − 7
- = 27 − 7 = 20
7.If x = 9 and y = −3, find the value of 6x2 + 2y
Answer: 480
- 6 × (9)² + 2 × (−3)
- = 486 − 6 = 480
8.If x = −1 and y = −1, find the value of 6x2 − 3y
Answer: 9
- 6 × (−1)² − 3 × (−1)
- = 6 + 3 = 9
9.If x = 8 and y = −2, find the value of 9x2 + 9y
Answer: 558
- 9 × (8)² + 9 × (−2)
- = 576 − 18 = 558
10.If x = −4 and y = −4, find the value of 5x2 + 5y
Answer: 60
- 5 × (−4)² + 5 × (−4)
- = 80 − 20 = 60
11.Find the value of 8x + 7 when x = 5
Answer: 47
- 8 × 5 + 7
- = 40 + 7 = 47
12.Find the value of −3x − 2 when x = 6
Answer: −20
- −3 × 6 − 2
- = −18 − 2 = −20
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