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 9x + 9 when x = 9
Answer: 90
- 9 × 9 + 9
- = 81 + 9 = 90
2.If x = 2 and y = −3, find the value of 9x2 + 6y
Answer: 18
- 9 × (2)² + 6 × (−3)
- = 36 − 18 = 18
3.Find the value of x + 1 when x = 7
Answer: 8
- 1 × 7 + 1
- = 7 + 1 = 8
4.If x = 1 and y = −2, find the value of x2 − 9y
Answer: 19
- 1 × (1)² − 9 × (−2)
- = 1 + 18 = 19
5.Find the value of −2x − 6 when x = −3
Answer: 0
- −2 × (−3) − 6
- = 6 − 6 = 0
6.If x = 1 and y = −3, find the value of −4x2 + 3y
Answer: −13
- −4 × (1)² + 3 × (−3)
- = −4 − 9 = −13
7.Find the value of 5x − 4 when x = 9
Answer: 41
- 5 × 9 − 4
- = 45 − 4 = 41
8.Find the value of −x − 2 when x = 4
Answer: −6
- −1 × 4 − 2
- = −4 − 2 = −6
9.Find the value of −5x + 7 when x = −6
Answer: 37
- −5 × (−6) + 7
- = 30 + 7 = 37
10.Find the value of 4x + 6 when x = 6
Answer: 30
- 4 × 6 + 6
- = 24 + 6 = 30
11.If x = 9 and y = 4, find the value of 3x2 + 3y
Answer: 255
- 3 × (9)² + 3 × (4)
- = 243 + 12 = 255
12.Find the value of 4x − 8 when x = −5
Answer: −28
- 4 × (−5) − 8
- = −20 − 8 = −28
Marking tips
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