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Class 8 Maths Worksheet: Algebraic Identities

Maths worksheets lesson 61: Algebraic identities · Set 495 · 40 sums
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The method (Split into easy parts): (a + b)² = a² + 2ab + b². (a − b)² = a² − 2ab + b². (a + b)(a − b) = a² − b²; so a² − b² = (a + b)(a − b). a² + b² = (a + b)² − 2ab = (a − b)² + 2ab.

NameDateTime takenScore ___ / 40
  1. 1.Find the value of x² − 2xy + y² when x = 3 and y = 2.
  2. 2.Use (a + b)(a − b) = a² − b² to find 24 × 16.
  3. 3.Use a² − b² = (a + b)(a − b) to find 22² − 9².
  4. 4.Use (a − b)² = a² − 2ab + b² to find 19².
  5. 5.If a + b = 6 and ab = 8, what is a² + b²?
  6. 6.Use (a + b)(a − b) = a² − b² to find 37 × 23.
  7. 7.If a + b = 8 and ab = 7, what is a² + b²?
  8. 8.Use a² − b² = (a + b)(a − b) to find 30² − 7².
  9. 9.Use (a − b)² = a² − 2ab + b² to find 58².
  10. 10.Use (a − b)² = a² − 2ab + b² to find 25².
  11. 11.Use a² − b² = (a + b)(a − b) to find 87² − 86².
  12. 12.Find the value of x² − 2xy + y² when x = 11 and y = 9.
  13. 13.Find the value of x² − y² when x = 15 and y = 9.
  14. 14.If a + b = 5 and ab = 6, what is a² + b²?
  15. 15.If a + b = 3 and ab = 2, what is a² + b²?
  16. 16.Use a² − b² = (a + b)(a − b) to find 21² − 13².
  17. 17.If a − b = 1 and ab = 20, what is a² + b²?
  18. 18.If a + b = 23 and ab = 132, what is a² + b²?
  19. 19.Use (a + b)(a − b) = a² − b² to find 33 × 27.
  20. 20.Find the value of x² + 2xy + y² when x = 11 and y = 1.
  21. 21.Use (a − b)² = a² − 2ab + b² to find 93².
  22. 22.If a − b = 3 and ab = 4, what is a² + b²?
  23. 23.Use (a + b)(a − b) = a² − b² to find 88 × 72.
  24. 24.Use a² − b² = (a + b)(a − b) to find 58² − 22².
  25. 25.Use (a − b)² = a² − 2ab + b² to find 54².
  26. 26.Use (a − b)² = a² − 2ab + b² to find 77².
  27. 27.Use (a + b)(a − b) = a² − b² to find 66 × 54.
  28. 28.Use (a + b)(a − b) = a² − b² to find 97 × 83.
  29. 29.Use (a + b)² = a² + 2ab + b² to find 109².
  30. 30.Use (a − b)² = a² − 2ab + b² to find 13².
  31. 31.Use (a + b)² = a² + 2ab + b² to find 56².
  32. 32.Use (a + b)(a − b) = a² − b² to find 31 × 29.
  33. 33.Use a² − b² = (a + b)(a − b) to find 79² − 71².
  34. 34.Use (a + b)² = a² + 2ab + b² to find 95².
  35. 35.Use a² − b² = (a + b)(a − b) to find 71² − 59².
  36. 36.Use (a + b)(a − b) = a² − b² to find 109 × 91.
  37. 37.Use (a + b)(a − b) = a² − b² to find 79 × 61.
  38. 38.Use (a + b)² = a² + 2ab + b² to find 29².
  39. 39.If a − b = 1 and ab = 132, what is a² + b²?
  40. 40.Use (a + b)² = a² + 2ab + b² to find 82².

Answer key

  1. 1
  2. 384
  3. 403
  4. 361
  5. 20
  6. 851
  7. 50
  8. 851
  9. 3364
  10. 625
  11. 173
  12. 4
  13. 144
  14. 13
  15. 5
  16. 272
  17. 41
  18. 265
  19. 891
  20. 144
  21. 8649
  22. 17
  23. 6336
  24. 2880
  25. 2916
  26. 5929
  27. 3564
  28. 8051
  29. 11881
  30. 169
  31. 3136
  32. 899
  33. 1200
  34. 9025
  35. 1560
  36. 9919
  37. 4819
  38. 841
  39. 265
  40. 6724

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