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Class 8 Maths Worksheet: Algebraic Identities

Maths worksheets lesson 61: Algebraic identities · Set 907 · 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 − 2xy + y² when x = 9 and y = 2.
  2. 2.Use (a + b)² = a² + 2ab + b² to find 31².
  3. 3.Use (a + b)² = a² + 2ab + b² to find 69².
  4. 4.Use (a − b)² = a² − 2ab + b² to find 97².
  5. 5.Use a² − b² = (a + b)(a − b) to find 52² − 31².
  6. 6.If a − b = 2 and ab = 3, what is a² + b²?
  7. 7.Use (a + b)(a − b) = a² − b² to find 105 × 95.
  8. 8.Use (a + b)² = a² + 2ab + b² to find 61².
  9. 9.Use (a + b)² = a² + 2ab + b² to find 12².
  10. 10.Use (a + b)² = a² + 2ab + b² to find 37².
  11. 11.Use (a − b)² = a² − 2ab + b² to find 14².
  12. 12.If a − b = 5 and ab = 36, what is a² + b²?
  13. 13.Use a² − b² = (a + b)(a − b) to find 95² − 9².
  14. 14.Use (a + b)² = a² + 2ab + b² to find 91².
  15. 15.Use a² − b² = (a + b)(a − b) to find 48² − 39².
  16. 16.If a + b = 4 and ab = 3, what is a² + b²?
  17. 17.Use a² − b² = (a + b)(a − b) to find 62² − 12².
  18. 18.Use (a − b)² = a² − 2ab + b² to find 11².
  19. 19.If a + b = 12 and ab = 27, what is a² + b²?
  20. 20.Use (a + b)² = a² + 2ab + b² to find 102².
  21. 21.Find the value of x² − 2xy + y² when x = 7 and y = 1.
  22. 22.Use a² − b² = (a + b)(a − b) to find 34² − 27².
  23. 23.Find the value of x² + 2xy + y² when x = 10 and y = 5.
  24. 24.If a − b = 7 and ab = 18, what is a² + b²?
  25. 25.Find the value of x² + 2xy + y² when x = 3 and y = 1.
  26. 26.Use (a − b)² = a² − 2ab + b² to find 76².
  27. 27.Find the value of x² + 2xy + y² when x = 6 and y = 4.
  28. 28.Use (a + b)² = a² + 2ab + b² to find 24².
  29. 29.Use (a + b)(a − b) = a² − b² to find 27 × 13.
  30. 30.Use (a + b)(a − b) = a² − b² to find 26 × 14.
  31. 31.Find the value of x² − y² when x = 7 and y = 2.
  32. 32.Use (a − b)² = a² − 2ab + b² to find 31².
  33. 33.Use (a + b)² = a² + 2ab + b² to find 104².
  34. 34.If a − b = 1 and ab = 20, what is a² + b²?
  35. 35.Use a² − b² = (a + b)(a − b) to find 68² − 16².
  36. 36.Find the value of x² − 2xy + y² when x = 11 and y = 6.
  37. 37.Use (a − b)² = a² − 2ab + b² to find 22².
  38. 38.Use a² − b² = (a + b)(a − b) to find 97² − 2².
  39. 39.Use (a − b)² = a² − 2ab + b² to find 46².
  40. 40.Use (a + b)(a − b) = a² − b² to find 39 × 21.

Answer key

  1. 49
  2. 961
  3. 4761
  4. 9409
  5. 1743
  6. 10
  7. 9975
  8. 3721
  9. 144
  10. 1369
  11. 196
  12. 97
  13. 8944
  14. 8281
  15. 783
  16. 10
  17. 3700
  18. 121
  19. 90
  20. 10404
  21. 36
  22. 427
  23. 225
  24. 85
  25. 16
  26. 5776
  27. 100
  28. 576
  29. 351
  30. 364
  31. 45
  32. 961
  33. 10816
  34. 41
  35. 4368
  36. 25
  37. 484
  38. 9405
  39. 2116
  40. 819

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