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Class 8 Maths Worksheet: Algebraic Identities

Maths worksheets lesson 61: Algebraic identities · Set 301 · 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.Find the value of x² − y² when x = 14 and y = 3.
  2. 2.Find the value of x² − y² when x = 5 and y = 1.
  3. 3.Use (a − b)² = a² − 2ab + b² to find 69².
  4. 4.Find the value of x² − 2xy + y² when x = 9 and y = 1.
  5. 5.Use (a + b)(a − b) = a² − b² to find 44 × 36.
  6. 6.Use a² − b² = (a + b)(a − b) to find 92² − 29².
  7. 7.Use a² − b² = (a + b)(a − b) to find 72² − 16².
  8. 8.If a + b = 6 and ab = 5, what is a² + b²?
  9. 9.Use (a + b)(a − b) = a² − b² to find 43 × 37.
  10. 10.Use (a − b)² = a² − 2ab + b² to find 66².
  11. 11.Use (a + b)² = a² + 2ab + b² to find 35².
  12. 12.Use (a + b)² = a² + 2ab + b² to find 57².
  13. 13.Use a² − b² = (a + b)(a − b) to find 22² − 1².
  14. 14.Use (a − b)² = a² − 2ab + b² to find 97².
  15. 15.Use (a + b)² = a² + 2ab + b² to find 54².
  16. 16.Use (a − b)² = a² − 2ab + b² to find 31².
  17. 17.Use a² − b² = (a + b)(a − b) to find 98² − 50².
  18. 18.Use (a + b)² = a² + 2ab + b² to find 44².
  19. 19.Use (a + b)² = a² + 2ab + b² to find 59².
  20. 20.Use (a + b)(a − b) = a² − b² to find 87 × 73.
  21. 21.Find the value of x² + 2xy + y² when x = 11 and y = 4.
  22. 22.Use a² − b² = (a + b)(a − b) to find 66² − 56².
  23. 23.Use (a + b)(a − b) = a² − b² to find 39 × 21.
  24. 24.Use a² − b² = (a + b)(a − b) to find 40² − 2².
  25. 25.Find the value of x² + 2xy + y² when x = 6 and y = 2.
  26. 26.Use (a − b)² = a² − 2ab + b² to find 68².
  27. 27.Use (a + b)(a − b) = a² − b² to find 37 × 23.
  28. 28.Use (a + b)² = a² + 2ab + b² to find 108².
  29. 29.Use (a + b)² = a² + 2ab + b² to find 83².
  30. 30.Use (a − b)² = a² − 2ab + b² to find 81².
  31. 31.Use (a + b)² = a² + 2ab + b² to find 65².
  32. 32.Find the value of x² − 2xy + y² when x = 4 and y = 2.
  33. 33.Use (a − b)² = a² − 2ab + b² to find 61².
  34. 34.Use (a + b)² = a² + 2ab + b² to find 63².
  35. 35.Use (a + b)² = a² + 2ab + b² to find 74².
  36. 36.Use (a + b)² = a² + 2ab + b² to find 62².
  37. 37.Use (a − b)² = a² − 2ab + b² to find 83².
  38. 38.Use (a − b)² = a² − 2ab + b² to find 49².
  39. 39.If a − b = 8 and ab = 9, what is a² + b²?
  40. 40.Use (a + b)² = a² + 2ab + b² to find 84².

Answer key

  1. 187
  2. 24
  3. 4761
  4. 64
  5. 1584
  6. 7623
  7. 4928
  8. 26
  9. 1591
  10. 4356
  11. 1225
  12. 3249
  13. 483
  14. 9409
  15. 2916
  16. 961
  17. 7104
  18. 1936
  19. 3481
  20. 6351
  21. 225
  22. 1220
  23. 819
  24. 1596
  25. 64
  26. 4624
  27. 851
  28. 11664
  29. 6889
  30. 6561
  31. 4225
  32. 4
  33. 3721
  34. 3969
  35. 5476
  36. 3844
  37. 6889
  38. 2401
  39. 82
  40. 7056

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