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Class 8 Maths Worksheet: Algebraic Identities

Maths worksheets lesson 61: Algebraic identities · Set 96 · 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 66².
  2. 2.Find the value of x² − y² when x = 7 and y = 3.
  3. 3.Use (a + b)(a − b) = a² − b² to find 44 × 36.
  4. 4.If a + b = 6 and ab = 5, what is a² + b²?
  5. 5.Use (a − b)² = a² − 2ab + b² to find 58².
  6. 6.Use (a + b)(a − b) = a² − b² to find 72 × 68.
  7. 7.Find the value of x² − 2xy + y² when x = 14 and y = 3.
  8. 8.If a − b = 10 and ab = 24, what is a² + b²?
  9. 9.Use (a + b)² = a² + 2ab + b² to find 25².
  10. 10.Use (a + b)² = a² + 2ab + b² to find 61².
  11. 11.If a − b = 3 and ab = 4, what is a² + b²?
  12. 12.Use (a − b)² = a² − 2ab + b² to find 72².
  13. 13.If a + b = 13 and ab = 36, what is a² + b²?
  14. 14.Use (a − b)² = a² − 2ab + b² to find 32².
  15. 15.Use (a + b)² = a² + 2ab + b² to find 78².
  16. 16.Use (a − b)² = a² − 2ab + b² to find 49².
  17. 17.If a − b = 3 and ab = 10, what is a² + b²?
  18. 18.If a − b = 1 and ab = 6, what is a² + b²?
  19. 19.Use (a − b)² = a² − 2ab + b² to find 96².
  20. 20.Use (a + b)(a − b) = a² − b² to find 36 × 24.
  21. 21.Use a² − b² = (a + b)(a − b) to find 31² − 19².
  22. 22.Use (a + b)(a − b) = a² − b² to find 74 × 66.
  23. 23.Find the value of x² − 2xy + y² when x = 11 and y = 2.
  24. 24.If a + b = 3 and ab = 2, what is a² + b²?
  25. 25.Use a² − b² = (a + b)(a − b) to find 99² − 89².
  26. 26.Use (a + b)² = a² + 2ab + b² to find 28².
  27. 27.Use (a + b)(a − b) = a² − b² to find 94 × 86.
  28. 28.Use (a + b)² = a² + 2ab + b² to find 23².
  29. 29.Use (a + b)(a − b) = a² − b² to find 78 × 62.
  30. 30.Use (a − b)² = a² − 2ab + b² to find 22².
  31. 31.Use (a − b)² = a² − 2ab + b² to find 33².
  32. 32.Use (a + b)(a − b) = a² − b² to find 43 × 37.
  33. 33.If a + b = 12 and ab = 27, what is a² + b²?
  34. 34.Find the value of x² + 2xy + y² when x = 3 and y = 1.
  35. 35.Use (a + b)² = a² + 2ab + b² to find 29².
  36. 36.Use (a + b)² = a² + 2ab + b² to find 101².
  37. 37.Use (a + b)² = a² + 2ab + b² to find 57².
  38. 38.Use a² − b² = (a + b)(a − b) to find 98² − 76².
  39. 39.Use (a − b)² = a² − 2ab + b² to find 57².
  40. 40.If a + b = 12 and ab = 11, what is a² + b²?

Answer key

  1. 4356
  2. 40
  3. 1584
  4. 26
  5. 3364
  6. 4896
  7. 121
  8. 148
  9. 625
  10. 3721
  11. 17
  12. 5184
  13. 97
  14. 1024
  15. 6084
  16. 2401
  17. 29
  18. 13
  19. 9216
  20. 864
  21. 600
  22. 4884
  23. 81
  24. 5
  25. 1880
  26. 784
  27. 8084
  28. 529
  29. 4836
  30. 484
  31. 1089
  32. 1591
  33. 90
  34. 16
  35. 841
  36. 10201
  37. 3249
  38. 3828
  39. 3249
  40. 122

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