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Class 8 Maths Worksheet: Algebraic Identities

Maths worksheets lesson 61: Algebraic identities · Set 561 · 40 sums
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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 a² − b² = (a + b)(a − b) to find 69² − 32².
  2. 2.Use (a + b)² = a² + 2ab + b² to find 35².
  3. 3.Use (a + b)² = a² + 2ab + b² to find 14².
  4. 4.Use a² − b² = (a + b)(a − b) to find 76² − 17².
  5. 5.Use (a + b)² = a² + 2ab + b² to find 63².
  6. 6.Use (a + b)² = a² + 2ab + b² to find 38².
  7. 7.Use (a + b)² = a² + 2ab + b² to find 34².
  8. 8.Use a² − b² = (a + b)(a − b) to find 97² − 52².
  9. 9.Use a² − b² = (a + b)(a − b) to find 64² − 4².
  10. 10.Find the value of x² − 2xy + y² when x = 9 and y = 1.
  11. 11.Use (a − b)² = a² − 2ab + b² to find 57².
  12. 12.Use a² − b² = (a + b)(a − b) to find 59² − 26².
  13. 13.Use (a − b)² = a² − 2ab + b² to find 17².
  14. 14.Use (a + b)² = a² + 2ab + b² to find 57².
  15. 15.Use (a + b)² = a² + 2ab + b² to find 73².
  16. 16.Use a² − b² = (a + b)(a − b) to find 91² − 26².
  17. 17.Use (a + b)(a − b) = a² − b² to find 58 × 42.
  18. 18.Use (a + b)² = a² + 2ab + b² to find 75².
  19. 19.If a − b = 1 and ab = 2, what is a² + b²?
  20. 20.Use a² − b² = (a + b)(a − b) to find 92² − 80².
  21. 21.Use a² − b² = (a + b)(a − b) to find 48² − 18².
  22. 22.Use (a + b)(a − b) = a² − b² to find 84 × 76.
  23. 23.Use a² − b² = (a + b)(a − b) to find 20² − 5².
  24. 24.Use (a + b)² = a² + 2ab + b² to find 29².
  25. 25.Use (a + b)² = a² + 2ab + b² to find 51².
  26. 26.Use (a + b)(a − b) = a² − b² to find 86 × 74.
  27. 27.Use (a + b)(a − b) = a² − b² to find 54 × 46.
  28. 28.Use a² − b² = (a + b)(a − b) to find 93² − 76².
  29. 29.Find the value of x² + 2xy + y² when x = 13 and y = 1.
  30. 30.Use (a − b)² = a² − 2ab + b² to find 67².
  31. 31.Use (a + b)² = a² + 2ab + b² to find 91².
  32. 32.Use (a + b)(a − b) = a² − b² to find 94 × 86.
  33. 33.Use (a + b)² = a² + 2ab + b² to find 43².
  34. 34.Use (a − b)² = a² − 2ab + b² to find 99².
  35. 35.Use (a + b)² = a² + 2ab + b² to find 109².
  36. 36.If a + b = 16 and ab = 48, what is a² + b²?
  37. 37.Find the value of x² − y² when x = 11 and y = 9.
  38. 38.If a − b = 2 and ab = 15, what is a² + b²?
  39. 39.Use (a − b)² = a² − 2ab + b² to find 16².
  40. 40.Use (a − b)² = a² − 2ab + b² to find 94².

Answer key

  1. 3737
  2. 1225
  3. 196
  4. 5487
  5. 3969
  6. 1444
  7. 1156
  8. 6705
  9. 4080
  10. 64
  11. 3249
  12. 2805
  13. 289
  14. 3249
  15. 5329
  16. 7605
  17. 2436
  18. 5625
  19. 5
  20. 2064
  21. 1980
  22. 6384
  23. 375
  24. 841
  25. 2601
  26. 6364
  27. 2484
  28. 2873
  29. 196
  30. 4489
  31. 8281
  32. 8084
  33. 1849
  34. 9801
  35. 11881
  36. 160
  37. 40
  38. 34
  39. 256
  40. 8836

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