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Class 8 Maths Worksheet: Algebraic Identities

Maths worksheets lesson 61: Algebraic identities · Set 938 · 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 = 8 and y = 6.
  2. 2.Use (a + b)² = a² + 2ab + b² to find 43².
  3. 3.Use (a + b)² = a² + 2ab + b² to find 86².
  4. 4.Use (a − b)² = a² − 2ab + b² to find 91².
  5. 5.Use (a − b)² = a² − 2ab + b² to find 27².
  6. 6.Use (a − b)² = a² − 2ab + b² to find 77².
  7. 7.Use a² − b² = (a + b)(a − b) to find 60² − 33².
  8. 8.Use (a + b)(a − b) = a² − b² to find 89 × 71.
  9. 9.Find the value of x² − y² when x = 10 and y = 6.
  10. 10.Use (a + b)² = a² + 2ab + b² to find 35².
  11. 11.Use (a + b)² = a² + 2ab + b² to find 14².
  12. 12.Use (a − b)² = a² − 2ab + b² to find 19².
  13. 13.Use (a − b)² = a² − 2ab + b² to find 14².
  14. 14.Find the value of x² − y² when x = 10 and y = 7.
  15. 15.If a + b = 3 and ab = 2, what is a² + b²?
  16. 16.If a + b = 22 and ab = 120, what is a² + b²?
  17. 17.Use (a + b)² = a² + 2ab + b² to find 73².
  18. 18.Use a² − b² = (a + b)(a − b) to find 42² − 39².
  19. 19.Use (a + b)(a − b) = a² − b² to find 73 × 67.
  20. 20.Use (a − b)² = a² − 2ab + b² to find 43².
  21. 21.Find the value of x² − 2xy + y² when x = 13 and y = 6.
  22. 22.If a − b = 2 and ab = 3, what is a² + b²?
  23. 23.Use a² − b² = (a + b)(a − b) to find 89² − 50².
  24. 24.Use (a + b)² = a² + 2ab + b² to find 33².
  25. 25.Find the value of x² + 2xy + y² when x = 6 and y = 3.
  26. 26.Use (a + b)² = a² + 2ab + b² to find 96².
  27. 27.Use a² − b² = (a + b)(a − b) to find 85² − 67².
  28. 28.Use (a − b)² = a² − 2ab + b² to find 45².
  29. 29.Use (a − b)² = a² − 2ab + b² to find 12².
  30. 30.Find the value of x² − 2xy + y² when x = 4 and y = 3.
  31. 31.Use (a + b)(a − b) = a² − b² to find 46 × 34.
  32. 32.Use (a + b)(a − b) = a² − b² to find 81 × 79.
  33. 33.Use (a − b)² = a² − 2ab + b² to find 11².
  34. 34.Use (a + b)² = a² + 2ab + b² to find 26².
  35. 35.Use (a + b)² = a² + 2ab + b² to find 59².
  36. 36.Find the value of x² − y² when x = 11 and y = 9.
  37. 37.Use (a + b)(a − b) = a² − b² to find 54 × 46.
  38. 38.If a − b = 3 and ab = 40, what is a² + b²?
  39. 39.Find the value of x² − 2xy + y² when x = 7 and y = 4.
  40. 40.Use (a + b)(a − b) = a² − b² to find 98 × 82.

Answer key

  1. 196
  2. 1849
  3. 7396
  4. 8281
  5. 729
  6. 5929
  7. 2511
  8. 6319
  9. 64
  10. 1225
  11. 196
  12. 361
  13. 196
  14. 51
  15. 5
  16. 244
  17. 5329
  18. 243
  19. 4891
  20. 1849
  21. 49
  22. 10
  23. 5421
  24. 1089
  25. 81
  26. 9216
  27. 2736
  28. 2025
  29. 144
  30. 1
  31. 1564
  32. 6399
  33. 121
  34. 676
  35. 3481
  36. 40
  37. 2484
  38. 89
  39. 9
  40. 8036

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