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Class 8 Maths Worksheet: Algebraic Identities

Maths worksheets lesson 61: Algebraic identities · Set 279 · 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 = 3 and y = 2.
  2. 2.If a − b = 1 and ab = 2, what is a² + b²?
  3. 3.Use (a − b)² = a² − 2ab + b² to find 66².
  4. 4.Use a² − b² = (a + b)(a − b) to find 40² − 23².
  5. 5.Find the value of x² + 2xy + y² when x = 4 and y = 1.
  6. 6.Use a² − b² = (a + b)(a − b) to find 23² − 19².
  7. 7.Find the value of x² − 2xy + y² when x = 12 and y = 3.
  8. 8.Use (a − b)² = a² − 2ab + b² to find 17².
  9. 9.Find the value of x² − 2xy + y² when x = 5 and y = 4.
  10. 10.Find the value of x² + 2xy + y² when x = 7 and y = 1.
  11. 11.Use (a + b)² = a² + 2ab + b² to find 52².
  12. 12.Use (a + b)² = a² + 2ab + b² to find 59².
  13. 13.Use (a + b)(a − b) = a² − b² to find 83 × 77.
  14. 14.Find the value of x² − y² when x = 5 and y = 2.
  15. 15.Use (a + b)² = a² + 2ab + b² to find 76².
  16. 16.Use (a + b)(a − b) = a² − b² to find 102 × 98.
  17. 17.Use a² − b² = (a + b)(a − b) to find 95² − 61².
  18. 18.Use (a − b)² = a² − 2ab + b² to find 33².
  19. 19.If a + b = 8 and ab = 7, what is a² + b²?
  20. 20.Find the value of x² + 2xy + y² when x = 10 and y = 4.
  21. 21.If a − b = 3 and ab = 88, what is a² + b²?
  22. 22.Use (a + b)(a − b) = a² − b² to find 43 × 37.
  23. 23.Use a² − b² = (a + b)(a − b) to find 99² − 86².
  24. 24.Find the value of x² − 2xy + y² when x = 12 and y = 6.
  25. 25.Find the value of x² − y² when x = 5 and y = 1.
  26. 26.Use (a + b)² = a² + 2ab + b² to find 11².
  27. 27.Use a² − b² = (a + b)(a − b) to find 80² − 61².
  28. 28.Use (a + b)(a − b) = a² − b² to find 61 × 59.
  29. 29.If a − b = 2 and ab = 35, what is a² + b²?
  30. 30.Use (a − b)² = a² − 2ab + b² to find 89².
  31. 31.Use (a − b)² = a² − 2ab + b² to find 11².
  32. 32.Use (a − b)² = a² − 2ab + b² to find 67².
  33. 33.If a − b = 1 and ab = 110, what is a² + b²?
  34. 34.Find the value of x² − 2xy + y² when x = 11 and y = 9.
  35. 35.Use (a − b)² = a² − 2ab + b² to find 42².
  36. 36.If a + b = 5 and ab = 6, what is a² + b²?
  37. 37.Use (a + b)² = a² + 2ab + b² to find 95².
  38. 38.Use (a + b)(a − b) = a² − b² to find 22 × 18.
  39. 39.Find the value of x² − 2xy + y² when x = 11 and y = 2.
  40. 40.Use (a − b)² = a² − 2ab + b² to find 73².

Answer key

  1. 5
  2. 5
  3. 4356
  4. 1071
  5. 25
  6. 168
  7. 81
  8. 289
  9. 1
  10. 64
  11. 2704
  12. 3481
  13. 6391
  14. 21
  15. 5776
  16. 9996
  17. 5304
  18. 1089
  19. 50
  20. 196
  21. 185
  22. 1591
  23. 2405
  24. 36
  25. 24
  26. 121
  27. 2679
  28. 3599
  29. 74
  30. 7921
  31. 121
  32. 4489
  33. 221
  34. 4
  35. 1764
  36. 13
  37. 9025
  38. 396
  39. 81
  40. 5329

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