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8th Grade Substitution Worksheet — Level 3 — Practice Set 3 — Answers

Answer sheet with worked solutions for the 8th Grade algebraic expressions worksheet.

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Success TutoringWorksheetsAnswer sheet8th Grade · Mathematics · Algebraic Expressions

8th Grade Substitution Worksheet — Level 3 — Practice Set 3 — Answers

Replace the letter with the number, then calculate. Use parentheses for negative values.

1.If x = 7 and y = 3, find the value of 4x2 + 9y

Answer: 223

  1. 4 × (7)² + 9 × (3)
  2. = 196 + 27 = 223
2.Find the value of 6x − 3 when x = 6

Answer: 33

  1. 6 × 6 − 3
  2. = 36 − 3 = 33
3.If x = 3 and y = 1, find the value of 2x2 + 5y

Answer: 23

  1. 2 × (3)² + 5 × (1)
  2. = 18 + 5 = 23
4.Find the value of −x + 9 when x = −1

Answer: 10

  1. −1 × (−1) + 9
  2. = 1 + 9 = 10
5.If x = 3 and y = −4, find the value of −5x2 + 9y

Answer: −81

  1. −5 × (3)² + 9 × (−4)
  2. = −45 − 36 = −81
6.If x = 5 and y = 6, find the value of 5x2 + y

Answer: 131

  1. 5 × (5)² + 1 × (6)
  2. = 125 + 6 = 131
7.Find the value of 7x − 7 when x = 9

Answer: 56

  1. 7 × 9 − 7
  2. = 63 − 7 = 56
8.If x = 8 and y = 2, find the value of 6x2 − 3y

Answer: 378

  1. 6 × (8)² − 3 × (2)
  2. = 384 − 6 = 378
9.If x = 3 and y = 5, find the value of −x2 − 5y

Answer: −34

  1. −1 × (3)² − 5 × (5)
  2. = −9 − 25 = −34
10.If x = 7 and y = −4, find the value of 8x2 + 6y

Answer: 368

  1. 8 × (7)² + 6 × (−4)
  2. = 392 − 24 = 368
11.If x = 5 and y = 3, find the value of 7x2 − 4y

Answer: 163

  1. 7 × (5)² − 4 × (3)
  2. = 175 − 12 = 163
12.If x = 9 and y = 2, find the value of 8x2 − 6y

Answer: 636

  1. 8 × (9)² − 6 × (2)
  2. = 648 − 12 = 636
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