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Class 8 Maths Worksheet: Algebraic Identities

Maths worksheets lesson 61: Algebraic identities · Set 758 · 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 a² − b² = (a + b)(a − b) to find 71² − 14².
  2. 2.Use a² − b² = (a + b)(a − b) to find 46² − 6².
  3. 3.Use a² − b² = (a + b)(a − b) to find 22² − 4².
  4. 4.Find the value of x² + 2xy + y² when x = 3 and y = 2.
  5. 5.Find the value of x² − 2xy + y² when x = 8 and y = 4.
  6. 6.Use (a + b)(a − b) = a² − b² to find 51 × 49.
  7. 7.Use (a − b)² = a² − 2ab + b² to find 18².
  8. 8.Use (a + b)(a − b) = a² − b² to find 46 × 34.
  9. 9.Use (a − b)² = a² − 2ab + b² to find 16².
  10. 10.Use (a + b)² = a² + 2ab + b² to find 68².
  11. 11.Use a² − b² = (a + b)(a − b) to find 63² − 1².
  12. 12.Use (a + b)(a − b) = a² − b² to find 34 × 26.
  13. 13.Use (a + b)² = a² + 2ab + b² to find 66².
  14. 14.Use (a + b)² = a² + 2ab + b² to find 101².
  15. 15.Use (a + b)(a − b) = a² − b² to find 54 × 46.
  16. 16.Use (a + b)² = a² + 2ab + b² to find 63².
  17. 17.Use (a + b)² = a² + 2ab + b² to find 11².
  18. 18.Use a² − b² = (a + b)(a − b) to find 42² − 36².
  19. 19.Use (a + b)(a − b) = a² − b² to find 68 × 52.
  20. 20.If a + b = 16 and ab = 60, what is a² + b²?
  21. 21.Use (a + b)(a − b) = a² − b² to find 107 × 93.
  22. 22.Use (a − b)² = a² − 2ab + b² to find 24².
  23. 23.Use a² − b² = (a + b)(a − b) to find 63² − 23².
  24. 24.Use (a + b)(a − b) = a² − b² to find 84 × 76.
  25. 25.Use (a − b)² = a² − 2ab + b² to find 13².
  26. 26.Use (a − b)² = a² − 2ab + b² to find 75².
  27. 27.If a + b = 7 and ab = 6, what is a² + b²?
  28. 28.Use a² − b² = (a + b)(a − b) to find 99² − 57².
  29. 29.Use a² − b² = (a + b)(a − b) to find 25² − 7².
  30. 30.Use (a − b)² = a² − 2ab + b² to find 63².
  31. 31.Use (a − b)² = a² − 2ab + b² to find 34².
  32. 32.Use (a + b)(a − b) = a² − b² to find 92 × 88.
  33. 33.Use (a + b)² = a² + 2ab + b² to find 106².
  34. 34.Find the value of x² + 2xy + y² when x = 10 and y = 4.
  35. 35.Use a² − b² = (a + b)(a − b) to find 65² − 5².
  36. 36.Use a² − b² = (a + b)(a − b) to find 28² − 20².
  37. 37.If a + b = 15 and ab = 56, what is a² + b²?
  38. 38.Use (a + b)² = a² + 2ab + b² to find 45².
  39. 39.Use (a + b)² = a² + 2ab + b² to find 48².
  40. 40.Use (a + b)² = a² + 2ab + b² to find 88².

Answer key

  1. 4845
  2. 2080
  3. 468
  4. 25
  5. 16
  6. 2499
  7. 324
  8. 1564
  9. 256
  10. 4624
  11. 3968
  12. 884
  13. 4356
  14. 10201
  15. 2484
  16. 3969
  17. 121
  18. 468
  19. 3536
  20. 136
  21. 9951
  22. 576
  23. 3440
  24. 6384
  25. 169
  26. 5625
  27. 37
  28. 6552
  29. 576
  30. 3969
  31. 1156
  32. 8096
  33. 11236
  34. 196
  35. 4200
  36. 384
  37. 113
  38. 2025
  39. 2304
  40. 7744

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