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Class 8 Maths Worksheet: Algebraic Identities

Maths worksheets lesson 61: Algebraic identities · Set 862 · 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)² = a² − 2ab + b² to find 73².
  2. 2.Use (a − b)² = a² − 2ab + b² to find 12².
  3. 3.Use a² − b² = (a + b)(a − b) to find 24² − 22².
  4. 4.Use (a + b)(a − b) = a² − b² to find 43 × 37.
  5. 5.Use a² − b² = (a + b)(a − b) to find 97² − 27².
  6. 6.Use (a − b)² = a² − 2ab + b² to find 19².
  7. 7.If a + b = 3 and ab = 2, what is a² + b²?
  8. 8.Use (a + b)(a − b) = a² − b² to find 55 × 45.
  9. 9.Use (a + b)(a − b) = a² − b² to find 73 × 67.
  10. 10.Use a² − b² = (a + b)(a − b) to find 91² − 17².
  11. 11.Find the value of x² − 2xy + y² when x = 7 and y = 5.
  12. 12.Use (a − b)² = a² − 2ab + b² to find 74².
  13. 13.Use (a + b)(a − b) = a² − b² to find 84 × 76.
  14. 14.Use (a − b)² = a² − 2ab + b² to find 66².
  15. 15.Use (a + b)² = a² + 2ab + b² to find 96².
  16. 16.If a + b = 10 and ab = 9, what is a² + b²?
  17. 17.Use (a + b)² = a² + 2ab + b² to find 54².
  18. 18.Use (a − b)² = a² − 2ab + b² to find 94².
  19. 19.Use (a − b)² = a² − 2ab + b² to find 65².
  20. 20.Find the value of x² − 2xy + y² when x = 12 and y = 6.
  21. 21.Use (a + b)(a − b) = a² − b² to find 75 × 65.
  22. 22.Use a² − b² = (a + b)(a − b) to find 38² − 17².
  23. 23.Use (a + b)² = a² + 2ab + b² to find 95².
  24. 24.Use a² − b² = (a + b)(a − b) to find 51² − 46².
  25. 25.If a + b = 4 and ab = 3, what is a² + b²?
  26. 26.Use (a + b)(a − b) = a² − b² to find 53 × 47.
  27. 27.Find the value of x² − y² when x = 5 and y = 2.
  28. 28.Use a² − b² = (a + b)(a − b) to find 83² − 37².
  29. 29.Use a² − b² = (a + b)(a − b) to find 38² − 18².
  30. 30.Use a² − b² = (a + b)(a − b) to find 23² − 5².
  31. 31.Find the value of x² + 2xy + y² when x = 8 and y = 2.
  32. 32.Use (a − b)² = a² − 2ab + b² to find 36².
  33. 33.Use a² − b² = (a + b)(a − b) to find 57² − 9².
  34. 34.Use (a + b)² = a² + 2ab + b² to find 18².
  35. 35.Use (a + b)² = a² + 2ab + b² to find 63².
  36. 36.Use (a − b)² = a² − 2ab + b² to find 26².
  37. 37.Find the value of x² − y² when x = 7 and y = 1.
  38. 38.Use (a − b)² = a² − 2ab + b² to find 89².
  39. 39.Use (a + b)² = a² + 2ab + b² to find 42².
  40. 40.Use (a + b)² = a² + 2ab + b² to find 88².

Answer key

  1. 5329
  2. 144
  3. 92
  4. 1591
  5. 8680
  6. 361
  7. 5
  8. 2475
  9. 4891
  10. 7992
  11. 4
  12. 5476
  13. 6384
  14. 4356
  15. 9216
  16. 82
  17. 2916
  18. 8836
  19. 4225
  20. 36
  21. 4875
  22. 1155
  23. 9025
  24. 485
  25. 10
  26. 2491
  27. 21
  28. 5520
  29. 1120
  30. 504
  31. 100
  32. 1296
  33. 3168
  34. 324
  35. 3969
  36. 676
  37. 48
  38. 7921
  39. 1764
  40. 7744

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