Year 8 Substitution Worksheet — Level 3 — Practice Set 4 — 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 4 — Answers
Replace the letter with the number, then calculate. Use brackets for negative values.
1.If x = 4 and y = −1, find the value of 3x2 − 9y
Answer: 57
- 3 × (4)² − 9 × (−1)
- = 48 + 9 = 57
2.Find the value of 5x − 5 when x = −3
Answer: −20
- 5 × (−3) − 5
- = −15 − 5 = −20
3.If x = 4 and y = −3, find the value of −2x2 + 6y
Answer: −50
- −2 × (4)² + 6 × (−3)
- = −32 − 18 = −50
4.If x = 6 and y = −5, find the value of −4x2 + 7y
Answer: −179
- −4 × (6)² + 7 × (−5)
- = −144 − 35 = −179
5.If x = 6 and y = 6, find the value of 3x2 − 5y
Answer: 78
- 3 × (6)² − 5 × (6)
- = 108 − 30 = 78
6.Find the value of −4x + 3 when x = 4
Answer: −13
- −4 × 4 + 3
- = −16 + 3 = −13
7.Find the value of 2x + 7 when x = −3
Answer: 1
- 2 × (−3) + 7
- = −6 + 7 = 1
8.If x = −3 and y = 1, find the value of 7x2 − 9y
Answer: 54
- 7 × (−3)² − 9 × (1)
- = 63 − 9 = 54
9.If x = −2 and y = −2, find the value of −3x2 + 2y
Answer: −16
- −3 × (−2)² + 2 × (−2)
- = −12 − 4 = −16
10.If x = −2 and y = −5, find the value of 4x2 − 8y
Answer: 56
- 4 × (−2)² − 8 × (−5)
- = 16 + 40 = 56
11.Find the value of 9x − 8 when x = −6
Answer: −62
- 9 × (−6) − 8
- = −54 − 8 = −62
12.If x = −5 and y = 1, find the value of 9x2 − 5y
Answer: 220
- 9 × (−5)² − 5 × (1)
- = 225 − 5 = 220
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