Year 9 Substitution Worksheet — Level 3 — Practice Set 4 — Answers
Answer sheet with worked solutions for the Year 9 algebraic expressions worksheet.
Success TutoringWorksheetsAnswer sheetYear 9 · Mathematics · Algebraic ExpressionsYear 9 Substitution Worksheet — Level 3 — Practice Set 4 — Answers
Replace the letter with the number, then calculate. Use brackets for negative values.
1.If x = 7 and y = −5, find the value of 3x2 + 9y
Answer: 102
- 3 × (7)² + 9 × (−5)
- = 147 − 45 = 102
2.Find the value of 3x + 9 when x = 1
Answer: 12
- 3 × 1 + 9
- = 3 + 9 = 12
3.Find the value of 4x − 3 when x = 4
Answer: 13
- 4 × 4 − 3
- = 16 − 3 = 13
4.Find the value of 4x − 9 when x = −2
Answer: −17
- 4 × (−2) − 9
- = −8 − 9 = −17
5.Find the value of 8x + 2 when x = −3
Answer: −22
- 8 × (−3) + 2
- = −24 + 2 = −22
6.Find the value of 5x − 8 when x = −1
Answer: −13
- 5 × (−1) − 8
- = −5 − 8 = −13
7.If x = −4 and y = 4, find the value of 9x2 − y
Answer: 140
- 9 × (−4)² − 1 × (4)
- = 144 − 4 = 140
8.If x = −3 and y = −5, find the value of 6x2 − y
Answer: 59
- 6 × (−3)² − 1 × (−5)
- = 54 + 5 = 59
9.Find the value of −5x + 1 when x = 4
Answer: −19
- −5 × 4 + 1
- = −20 + 1 = −19
10.If x = 4 and y = −5, find the value of 2x2 − 2y
Answer: 42
- 2 × (4)² − 2 × (−5)
- = 32 + 10 = 42
11.If x = 1 and y = −5, find the value of 3x2 + 8y
Answer: −37
- 3 × (1)² + 8 × (−5)
- = 3 − 40 = −37
12.If x = 8 and y = −5, find the value of −4x2 + 5y
Answer: −281
- −4 × (8)² + 5 × (−5)
- = −256 − 25 = −281
Marking tips
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