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Class 8 Maths Worksheet: Algebraic Identities

Maths worksheets lesson 61: Algebraic identities · Set 313 · 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 59².
  2. 2.If a + b = 6 and ab = 8, what is a² + b²?
  3. 3.Use a² − b² = (a + b)(a − b) to find 35² − 27².
  4. 4.Use (a + b)(a − b) = a² − b² to find 102 × 98.
  5. 5.Use (a + b)(a − b) = a² − b² to find 78 × 62.
  6. 6.Use a² − b² = (a + b)(a − b) to find 50² − 32².
  7. 7.Use (a + b)² = a² + 2ab + b² to find 78².
  8. 8.Find the value of x² − y² when x = 5 and y = 4.
  9. 9.If a + b = 5 and ab = 4, what is a² + b²?
  10. 10.Use (a − b)² = a² − 2ab + b² to find 52².
  11. 11.Use (a + b)(a − b) = a² − b² to find 103 × 97.
  12. 12.Find the value of x² − 2xy + y² when x = 4 and y = 3.
  13. 13.Use (a + b)(a − b) = a² − b² to find 62 × 58.
  14. 14.Use (a − b)² = a² − 2ab + b² to find 31².
  15. 15.If a − b = 5 and ab = 6, what is a² + b²?
  16. 16.Use (a + b)² = a² + 2ab + b² to find 96².
  17. 17.Find the value of x² + 2xy + y² when x = 4 and y = 3.
  18. 18.Use (a − b)² = a² − 2ab + b² to find 86².
  19. 19.Find the value of x² − 2xy + y² when x = 4 and y = 2.
  20. 20.Find the value of x² − y² when x = 12 and y = 11.
  21. 21.Use (a − b)² = a² − 2ab + b² to find 16².
  22. 22.Use (a + b)² = a² + 2ab + b² to find 28².
  23. 23.Use (a − b)² = a² − 2ab + b² to find 85².
  24. 24.If a + b = 7 and ab = 6, what is a² + b²?
  25. 25.Use (a + b)² = a² + 2ab + b² to find 22².
  26. 26.Use (a + b)(a − b) = a² − b² to find 27 × 13.
  27. 27.If a − b = 5 and ab = 24, what is a² + b²?
  28. 28.Use a² − b² = (a + b)(a − b) to find 33² − 8².
  29. 29.Use (a − b)² = a² − 2ab + b² to find 92².
  30. 30.Use a² − b² = (a + b)(a − b) to find 41² − 29².
  31. 31.Use (a − b)² = a² − 2ab + b² to find 61².
  32. 32.Use (a + b)² = a² + 2ab + b² to find 68².
  33. 33.Find the value of x² − y² when x = 12 and y = 8.
  34. 34.Use (a − b)² = a² − 2ab + b² to find 37².
  35. 35.Use (a − b)² = a² − 2ab + b² to find 39².
  36. 36.If a + b = 5 and ab = 6, what is a² + b²?
  37. 37.If a − b = 2 and ab = 8, what is a² + b²?
  38. 38.Use (a + b)² = a² + 2ab + b² to find 54².
  39. 39.Use a² − b² = (a + b)(a − b) to find 78² − 35².
  40. 40.Use (a + b)² = a² + 2ab + b² to find 67².

Answer key

  1. 3481
  2. 20
  3. 496
  4. 9996
  5. 4836
  6. 1476
  7. 6084
  8. 9
  9. 17
  10. 2704
  11. 9991
  12. 1
  13. 3596
  14. 961
  15. 37
  16. 9216
  17. 49
  18. 7396
  19. 4
  20. 23
  21. 256
  22. 784
  23. 7225
  24. 37
  25. 484
  26. 351
  27. 73
  28. 1025
  29. 8464
  30. 840
  31. 3721
  32. 4624
  33. 80
  34. 1369
  35. 1521
  36. 13
  37. 20
  38. 2916
  39. 4859
  40. 4489

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