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Class 8 Maths Worksheet: Algebraic Identities

Maths worksheets lesson 61: Algebraic identities · Set 373 · 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 + 2xy + y² when x = 4 and y = 3.
  2. 2.Use a² − b² = (a + b)(a − b) to find 90² − 29².
  3. 3.Use (a − b)² = a² − 2ab + b² to find 61².
  4. 4.Use (a + b)² = a² + 2ab + b² to find 18².
  5. 5.Use (a + b)² = a² + 2ab + b² to find 77².
  6. 6.Use (a + b)² = a² + 2ab + b² to find 11².
  7. 7.Use a² − b² = (a + b)(a − b) to find 59² − 49².
  8. 8.If a − b = 3 and ab = 70, what is a² + b²?
  9. 9.If a − b = 4 and ab = 12, what is a² + b²?
  10. 10.Find the value of x² + 2xy + y² when x = 11 and y = 8.
  11. 11.Use (a − b)² = a² − 2ab + b² to find 73².
  12. 12.Use a² − b² = (a + b)(a − b) to find 98² − 59².
  13. 13.Use (a − b)² = a² − 2ab + b² to find 16².
  14. 14.Find the value of x² + 2xy + y² when x = 15 and y = 11.
  15. 15.If a + b = 3 and ab = 2, what is a² + b²?
  16. 16.Use (a − b)² = a² − 2ab + b² to find 44².
  17. 17.Use a² − b² = (a + b)(a − b) to find 23² − 12².
  18. 18.Use (a + b)(a − b) = a² − b² to find 47 × 33.
  19. 19.Use (a − b)² = a² − 2ab + b² to find 88².
  20. 20.Use (a + b)² = a² + 2ab + b² to find 49².
  21. 21.Use (a + b)² = a² + 2ab + b² to find 12².
  22. 22.Use (a − b)² = a² − 2ab + b² to find 29².
  23. 23.Use (a + b)² = a² + 2ab + b² to find 16².
  24. 24.Use a² − b² = (a + b)(a − b) to find 74² − 62².
  25. 25.Use (a − b)² = a² − 2ab + b² to find 45².
  26. 26.Use (a + b)(a − b) = a² − b² to find 105 × 95.
  27. 27.Find the value of x² + 2xy + y² when x = 3 and y = 2.
  28. 28.Use (a + b)² = a² + 2ab + b² to find 22².
  29. 29.Use (a + b)² = a² + 2ab + b² to find 74².
  30. 30.Use (a + b)(a − b) = a² − b² to find 55 × 45.
  31. 31.Use (a + b)² = a² + 2ab + b² to find 43².
  32. 32.Use (a + b)² = a² + 2ab + b² to find 53².
  33. 33.Use (a + b)(a − b) = a² − b² to find 73 × 67.
  34. 34.Use (a + b)(a − b) = a² − b² to find 65 × 55.
  35. 35.Use (a + b)² = a² + 2ab + b² to find 63².
  36. 36.Use a² − b² = (a + b)(a − b) to find 66² − 9².
  37. 37.Find the value of x² − y² when x = 5 and y = 3.
  38. 38.Use (a + b)² = a² + 2ab + b² to find 108².
  39. 39.If a + b = 15 and ab = 44, what is a² + b²?
  40. 40.Use (a + b)(a − b) = a² − b² to find 45 × 35.

Answer key

  1. 49
  2. 7259
  3. 3721
  4. 324
  5. 5929
  6. 121
  7. 1080
  8. 149
  9. 40
  10. 361
  11. 5329
  12. 6123
  13. 256
  14. 676
  15. 5
  16. 1936
  17. 385
  18. 1551
  19. 7744
  20. 2401
  21. 144
  22. 841
  23. 256
  24. 1632
  25. 2025
  26. 9975
  27. 25
  28. 484
  29. 5476
  30. 2475
  31. 1849
  32. 2809
  33. 4891
  34. 3575
  35. 3969
  36. 4275
  37. 16
  38. 11664
  39. 137
  40. 1575

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