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Class 8 Maths Worksheet: Algebraic Identities

Maths worksheets lesson 61: Algebraic identities · Set 238 · 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 82².
  2. 2.Use (a + b)(a − b) = a² − b² to find 48 × 32.
  3. 3.Find the value of x² − 2xy + y² when x = 10 and y = 1.
  4. 4.If a − b = 8 and ab = 33, what is a² + b²?
  5. 5.Use (a − b)² = a² − 2ab + b² to find 37².
  6. 6.Find the value of x² − y² when x = 6 and y = 3.
  7. 7.If a + b = 3 and ab = 2, what is a² + b²?
  8. 8.Use (a + b)² = a² + 2ab + b² to find 41².
  9. 9.Use a² − b² = (a + b)(a − b) to find 39² − 36².
  10. 10.Find the value of x² − 2xy + y² when x = 5 and y = 3.
  11. 11.Find the value of x² − 2xy + y² when x = 14 and y = 9.
  12. 12.If a − b = 2 and ab = 3, what is a² + b²?
  13. 13.Use (a + b)² = a² + 2ab + b² to find 103².
  14. 14.Use (a − b)² = a² − 2ab + b² to find 69².
  15. 15.Find the value of x² + 2xy + y² when x = 13 and y = 6.
  16. 16.Use (a − b)² = a² − 2ab + b² to find 54².
  17. 17.Use a² − b² = (a + b)(a − b) to find 87² − 86².
  18. 18.Use (a + b)(a − b) = a² − b² to find 107 × 93.
  19. 19.Find the value of x² − y² when x = 6 and y = 4.
  20. 20.Find the value of x² − 2xy + y² when x = 7 and y = 4.
  21. 21.Find the value of x² + 2xy + y² when x = 14 and y = 10.
  22. 22.If a + b = 20 and ab = 96, what is a² + b²?
  23. 23.Use (a + b)(a − b) = a² − b² to find 108 × 92.
  24. 24.Use (a + b)² = a² + 2ab + b² to find 83².
  25. 25.Use a² − b² = (a + b)(a − b) to find 61² − 16².
  26. 26.Use (a + b)² = a² + 2ab + b² to find 67².
  27. 27.If a + b = 13 and ab = 36, what is a² + b²?
  28. 28.Find the value of x² − y² when x = 15 and y = 13.
  29. 29.Use (a + b)² = a² + 2ab + b² to find 14².
  30. 30.Use (a + b)(a − b) = a² − b² to find 41 × 39.
  31. 31.Use a² − b² = (a + b)(a − b) to find 55² − 41².
  32. 32.Use (a − b)² = a² − 2ab + b² to find 38².
  33. 33.Use (a + b)² = a² + 2ab + b² to find 38².
  34. 34.Use (a + b)² = a² + 2ab + b² to find 104².
  35. 35.Use (a − b)² = a² − 2ab + b² to find 47².
  36. 36.Use (a + b)(a − b) = a² − b² to find 109 × 91.
  37. 37.Use (a + b)² = a² + 2ab + b² to find 45².
  38. 38.Use (a − b)² = a² − 2ab + b² to find 76².
  39. 39.Find the value of x² + 2xy + y² when x = 5 and y = 3.
  40. 40.Use a² − b² = (a + b)(a − b) to find 62² − 25².

Answer key

  1. 6724
  2. 1536
  3. 81
  4. 130
  5. 1369
  6. 27
  7. 5
  8. 1681
  9. 225
  10. 4
  11. 25
  12. 10
  13. 10609
  14. 4761
  15. 361
  16. 2916
  17. 173
  18. 9951
  19. 20
  20. 9
  21. 576
  22. 208
  23. 9936
  24. 6889
  25. 3465
  26. 4489
  27. 97
  28. 56
  29. 196
  30. 1599
  31. 1344
  32. 1444
  33. 1444
  34. 10816
  35. 2209
  36. 9919
  37. 2025
  38. 5776
  39. 64
  40. 3219

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