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Class 8 Maths Worksheet: Algebraic Identities

Maths worksheets lesson 61: Algebraic identities · Set 526 · 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 (a − b)² = a² − 2ab + b² to find 64².
  2. 2.Find the value of x² + 2xy + y² when x = 13 and y = 9.
  3. 3.If a + b = 8 and ab = 15, what is a² + b²?
  4. 4.Use (a + b)² = a² + 2ab + b² to find 101².
  5. 5.If a + b = 22 and ab = 120, what is a² + b²?
  6. 6.Use (a + b)(a − b) = a² − b² to find 59 × 41.
  7. 7.Use (a + b)(a − b) = a² − b² to find 53 × 47.
  8. 8.Find the value of x² + 2xy + y² when x = 4 and y = 3.
  9. 9.Find the value of x² + 2xy + y² when x = 5 and y = 1.
  10. 10.Use (a + b)(a − b) = a² − b² to find 64 × 56.
  11. 11.Use (a − b)² = a² − 2ab + b² to find 88².
  12. 12.Use (a + b)(a − b) = a² − b² to find 29 × 11.
  13. 13.If a + b = 5 and ab = 6, what is a² + b²?
  14. 14.Find the value of x² − y² when x = 10 and y = 8.
  15. 15.Use (a − b)² = a² − 2ab + b² to find 11².
  16. 16.Use (a − b)² = a² − 2ab + b² to find 62².
  17. 17.Find the value of x² + 2xy + y² when x = 6 and y = 5.
  18. 18.Use (a + b)² = a² + 2ab + b² to find 63².
  19. 19.If a − b = 1 and ab = 2, what is a² + b²?
  20. 20.Find the value of x² + 2xy + y² when x = 6 and y = 4.
  21. 21.Use (a − b)² = a² − 2ab + b² to find 82².
  22. 22.Use (a + b)(a − b) = a² − b² to find 51 × 49.
  23. 23.Find the value of x² − 2xy + y² when x = 12 and y = 10.
  24. 24.Use (a + b)(a − b) = a² − b² to find 101 × 99.
  25. 25.Use (a + b)² = a² + 2ab + b² to find 27².
  26. 26.Use (a + b)(a − b) = a² − b² to find 105 × 95.
  27. 27.Use (a + b)² = a² + 2ab + b² to find 36².
  28. 28.If a + b = 7 and ab = 12, what is a² + b²?
  29. 29.Use (a + b)² = a² + 2ab + b² to find 51².
  30. 30.Use (a + b)(a − b) = a² − b² to find 41 × 39.
  31. 31.Find the value of x² − 2xy + y² when x = 14 and y = 1.
  32. 32.Use (a − b)² = a² − 2ab + b² to find 73².
  33. 33.Use (a − b)² = a² − 2ab + b² to find 39².
  34. 34.Use (a − b)² = a² − 2ab + b² to find 94².
  35. 35.Find the value of x² + 2xy + y² when x = 3 and y = 1.
  36. 36.Use (a − b)² = a² − 2ab + b² to find 13².
  37. 37.Use a² − b² = (a + b)(a − b) to find 68² − 6².
  38. 38.Find the value of x² + 2xy + y² when x = 5 and y = 2.
  39. 39.Use (a − b)² = a² − 2ab + b² to find 53².
  40. 40.Use (a + b)(a − b) = a² − b² to find 32 × 28.

Answer key

  1. 4096
  2. 484
  3. 34
  4. 10201
  5. 244
  6. 2419
  7. 2491
  8. 49
  9. 36
  10. 3584
  11. 7744
  12. 319
  13. 13
  14. 36
  15. 121
  16. 3844
  17. 121
  18. 3969
  19. 5
  20. 100
  21. 6724
  22. 2499
  23. 4
  24. 9999
  25. 729
  26. 9975
  27. 1296
  28. 25
  29. 2601
  30. 1599
  31. 169
  32. 5329
  33. 1521
  34. 8836
  35. 16
  36. 169
  37. 4588
  38. 49
  39. 2809
  40. 896

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