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Class 8 Maths Worksheet: Algebraic Identities

Maths worksheets lesson 61: Algebraic identities · Set 638 · 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.Use (a + b)(a − b) = a² − b² to find 52 × 48.
  2. 2.Use (a − b)² = a² − 2ab + b² to find 53².
  3. 3.Use (a − b)² = a² − 2ab + b² to find 26².
  4. 4.Use (a + b)(a − b) = a² − b² to find 22 × 18.
  5. 5.Use (a + b)(a − b) = a² − b² to find 58 × 42.
  6. 6.Use (a − b)² = a² − 2ab + b² to find 27².
  7. 7.Use (a − b)² = a² − 2ab + b² to find 35².
  8. 8.Use a² − b² = (a + b)(a − b) to find 96² − 53².
  9. 9.Use a² − b² = (a + b)(a − b) to find 49² − 27².
  10. 10.Use (a − b)² = a² − 2ab + b² to find 14².
  11. 11.Use (a + b)² = a² + 2ab + b² to find 76².
  12. 12.Use a² − b² = (a + b)(a − b) to find 59² − 12².
  13. 13.Use (a + b)(a − b) = a² − b² to find 95 × 85.
  14. 14.Use a² − b² = (a + b)(a − b) to find 58² − 8².
  15. 15.Use (a + b)(a − b) = a² − b² to find 103 × 97.
  16. 16.Use a² − b² = (a + b)(a − b) to find 69² − 12².
  17. 17.Use (a + b)² = a² + 2ab + b² to find 103².
  18. 18.Use (a + b)² = a² + 2ab + b² to find 79².
  19. 19.Use a² − b² = (a + b)(a − b) to find 49² − 40².
  20. 20.Use (a + b)(a − b) = a² − b² to find 63 × 57.
  21. 21.Find the value of x² + 2xy + y² when x = 12 and y = 4.
  22. 22.Use (a − b)² = a² − 2ab + b² to find 19².
  23. 23.If a + b = 4 and ab = 3, what is a² + b²?
  24. 24.Use (a + b)² = a² + 2ab + b² to find 21².
  25. 25.If a − b = 1 and ab = 30, what is a² + b²?
  26. 26.Use (a − b)² = a² − 2ab + b² to find 98².
  27. 27.Find the value of x² − y² when x = 8 and y = 3.
  28. 28.Use (a − b)² = a² − 2ab + b² to find 11².
  29. 29.Use (a + b)² = a² + 2ab + b² to find 31².
  30. 30.Use (a + b)² = a² + 2ab + b² to find 26².
  31. 31.Find the value of x² + 2xy + y² when x = 3 and y = 2.
  32. 32.Use (a − b)² = a² − 2ab + b² to find 77².
  33. 33.If a − b = 1 and ab = 2, what is a² + b²?
  34. 34.If a + b = 10 and ab = 16, what is a² + b²?
  35. 35.Find the value of x² − y² when x = 3 and y = 2.
  36. 36.Use a² − b² = (a + b)(a − b) to find 54² − 42².
  37. 37.Use (a + b)(a − b) = a² − b² to find 68 × 52.
  38. 38.Find the value of x² + 2xy + y² when x = 4 and y = 2.
  39. 39.Use a² − b² = (a + b)(a − b) to find 93² − 32².
  40. 40.Find the value of x² − y² when x = 13 and y = 3.

Answer key

  1. 2496
  2. 2809
  3. 676
  4. 396
  5. 2436
  6. 729
  7. 1225
  8. 6407
  9. 1672
  10. 196
  11. 5776
  12. 3337
  13. 8075
  14. 3300
  15. 9991
  16. 4617
  17. 10609
  18. 6241
  19. 801
  20. 3591
  21. 256
  22. 361
  23. 10
  24. 441
  25. 61
  26. 9604
  27. 55
  28. 121
  29. 961
  30. 676
  31. 25
  32. 5929
  33. 5
  34. 68
  35. 5
  36. 1152
  37. 3536
  38. 36
  39. 7625
  40. 160

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