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Class 8 Maths Worksheet: Algebraic Identities

Maths worksheets lesson 61: Algebraic identities · Set 514 · 40 sums
TalentJR

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 − y² when x = 11 and y = 6.
  2. 2.Use a² − b² = (a + b)(a − b) to find 99² − 86².
  3. 3.Find the value of x² − 2xy + y² when x = 11 and y = 7.
  4. 4.Use (a − b)² = a² − 2ab + b² to find 73².
  5. 5.Find the value of x² − 2xy + y² when x = 3 and y = 2.
  6. 6.Find the value of x² + 2xy + y² when x = 6 and y = 1.
  7. 7.If a + b = 14 and ab = 48, what is a² + b²?
  8. 8.Use (a + b)² = a² + 2ab + b² to find 84².
  9. 9.Use (a + b)(a − b) = a² − b² to find 32 × 28.
  10. 10.Use (a − b)² = a² − 2ab + b² to find 86².
  11. 11.Use (a + b)² = a² + 2ab + b² to find 99².
  12. 12.Use (a + b)(a − b) = a² − b² to find 94 × 86.
  13. 13.Use a² − b² = (a + b)(a − b) to find 54² − 1².
  14. 14.Find the value of x² − y² when x = 5 and y = 1.
  15. 15.Use a² − b² = (a + b)(a − b) to find 47² − 29².
  16. 16.Use (a − b)² = a² − 2ab + b² to find 22².
  17. 17.Use a² − b² = (a + b)(a − b) to find 37² − 27².
  18. 18.Use a² − b² = (a + b)(a − b) to find 74² − 12².
  19. 19.Use (a + b)(a − b) = a² − b² to find 109 × 91.
  20. 20.Use (a + b)(a − b) = a² − b² to find 76 × 64.
  21. 21.Find the value of x² − 2xy + y² when x = 12 and y = 5.
  22. 22.Find the value of x² − 2xy + y² when x = 14 and y = 12.
  23. 23.Use (a + b)² = a² + 2ab + b² to find 106².
  24. 24.Use (a + b)² = a² + 2ab + b² to find 94².
  25. 25.Use (a − b)² = a² − 2ab + b² to find 23².
  26. 26.Use (a − b)² = a² − 2ab + b² to find 42².
  27. 27.Use (a + b)² = a² + 2ab + b² to find 88².
  28. 28.Use (a + b)(a − b) = a² − b² to find 36 × 24.
  29. 29.Use (a + b)² = a² + 2ab + b² to find 19².
  30. 30.Use (a + b)² = a² + 2ab + b² to find 23².
  31. 31.Find the value of x² + 2xy + y² when x = 5 and y = 4.
  32. 32.Use (a − b)² = a² − 2ab + b² to find 85².
  33. 33.Use (a + b)(a − b) = a² − b² to find 31 × 29.
  34. 34.Use (a + b)(a − b) = a² − b² to find 62 × 58.
  35. 35.Find the value of x² − y² when x = 6 and y = 5.
  36. 36.Find the value of x² − 2xy + y² when x = 8 and y = 5.
  37. 37.Use (a + b)² = a² + 2ab + b² to find 54².
  38. 38.Use (a − b)² = a² − 2ab + b² to find 71².
  39. 39.Use a² − b² = (a + b)(a − b) to find 87² − 36².
  40. 40.Use (a + b)² = a² + 2ab + b² to find 89².

Answer key

  1. 85
  2. 2405
  3. 16
  4. 5329
  5. 1
  6. 49
  7. 100
  8. 7056
  9. 896
  10. 7396
  11. 9801
  12. 8084
  13. 2915
  14. 24
  15. 1368
  16. 484
  17. 640
  18. 5332
  19. 9919
  20. 4864
  21. 49
  22. 4
  23. 11236
  24. 8836
  25. 529
  26. 1764
  27. 7744
  28. 864
  29. 361
  30. 529
  31. 81
  32. 7225
  33. 899
  34. 3596
  35. 11
  36. 9
  37. 2916
  38. 5041
  39. 6273
  40. 7921

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