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Class 8 Maths Worksheet: Algebraic Identities

Maths worksheets lesson 61: Algebraic identities · Set 983 · 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 37 × 23.
  2. 2.Use (a + b)(a − b) = a² − b² to find 46 × 34.
  3. 3.Use (a − b)² = a² − 2ab + b² to find 41².
  4. 4.Use (a − b)² = a² − 2ab + b² to find 11².
  5. 5.Use (a − b)² = a² − 2ab + b² to find 75².
  6. 6.Use (a + b)² = a² + 2ab + b² to find 39².
  7. 7.Use (a + b)² = a² + 2ab + b² to find 66².
  8. 8.Use a² − b² = (a + b)(a − b) to find 77² − 1².
  9. 9.Use (a + b)² = a² + 2ab + b² to find 103².
  10. 10.Use (a + b)² = a² + 2ab + b² to find 86².
  11. 11.Use (a − b)² = a² − 2ab + b² to find 58².
  12. 12.Find the value of x² − 2xy + y² when x = 8 and y = 2.
  13. 13.Use (a − b)² = a² − 2ab + b² to find 21².
  14. 14.Find the value of x² − y² when x = 5 and y = 3.
  15. 15.Use (a + b)(a − b) = a² − b² to find 31 × 29.
  16. 16.Use (a + b)(a − b) = a² − b² to find 48 × 32.
  17. 17.Find the value of x² − y² when x = 9 and y = 6.
  18. 18.If a − b = 4 and ab = 21, what is a² + b²?
  19. 19.Use (a + b)² = a² + 2ab + b² to find 91².
  20. 20.Use (a + b)² = a² + 2ab + b² to find 57².
  21. 21.Use (a + b)(a − b) = a² − b² to find 67 × 53.
  22. 22.Use (a − b)² = a² − 2ab + b² to find 18².
  23. 23.Use (a + b)² = a² + 2ab + b² to find 55².
  24. 24.Use (a − b)² = a² − 2ab + b² to find 33².
  25. 25.If a − b = 3 and ab = 70, what is a² + b²?
  26. 26.Use (a + b)(a − b) = a² − b² to find 83 × 77.
  27. 27.Use (a − b)² = a² − 2ab + b² to find 47².
  28. 28.If a + b = 15 and ab = 56, what is a² + b²?
  29. 29.Use (a + b)(a − b) = a² − b² to find 33 × 27.
  30. 30.Use (a − b)² = a² − 2ab + b² to find 15².
  31. 31.Use (a + b)² = a² + 2ab + b² to find 71².
  32. 32.Find the value of x² − 2xy + y² when x = 12 and y = 5.
  33. 33.Use (a + b)(a − b) = a² − b² to find 102 × 98.
  34. 34.Use (a − b)² = a² − 2ab + b² to find 57².
  35. 35.Use (a + b)² = a² + 2ab + b² to find 104².
  36. 36.Use (a + b)² = a² + 2ab + b² to find 47².
  37. 37.Use (a + b)² = a² + 2ab + b² to find 31².
  38. 38.Find the value of x² − 2xy + y² when x = 8 and y = 1.
  39. 39.Use a² − b² = (a + b)(a − b) to find 72² − 52².
  40. 40.Use (a + b)² = a² + 2ab + b² to find 42².

Answer key

  1. 851
  2. 1564
  3. 1681
  4. 121
  5. 5625
  6. 1521
  7. 4356
  8. 5928
  9. 10609
  10. 7396
  11. 3364
  12. 36
  13. 441
  14. 16
  15. 899
  16. 1536
  17. 45
  18. 58
  19. 8281
  20. 3249
  21. 3551
  22. 324
  23. 3025
  24. 1089
  25. 149
  26. 6391
  27. 2209
  28. 113
  29. 891
  30. 225
  31. 5041
  32. 49
  33. 9996
  34. 3249
  35. 10816
  36. 2209
  37. 961
  38. 49
  39. 2480
  40. 1764

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