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Class 8 Maths Worksheet: Algebraic Identities

Maths worksheets lesson 61: Algebraic identities · Set 694 · 40 sums
TalentJR

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 = 11 and y = 1.
  2. 2.Use a² − b² = (a + b)(a − b) to find 83² − 64².
  3. 3.Find the value of x² − y² when x = 3 and y = 2.
  4. 4.Use (a + b)² = a² + 2ab + b² to find 36².
  5. 5.Use (a − b)² = a² − 2ab + b² to find 17².
  6. 6.Use a² − b² = (a + b)(a − b) to find 60² − 44².
  7. 7.Use (a + b)(a − b) = a² − b² to find 21 × 19.
  8. 8.If a + b = 4 and ab = 3, what is a² + b²?
  9. 9.If a + b = 15 and ab = 44, what is a² + b²?
  10. 10.Find the value of x² − 2xy + y² when x = 10 and y = 8.
  11. 11.Use a² − b² = (a + b)(a − b) to find 63² − 46².
  12. 12.If a + b = 10 and ab = 24, what is a² + b²?
  13. 13.Find the value of x² + 2xy + y² when x = 12 and y = 10.
  14. 14.Find the value of x² − 2xy + y² when x = 12 and y = 4.
  15. 15.Use (a − b)² = a² − 2ab + b² to find 19².
  16. 16.Use a² − b² = (a + b)(a − b) to find 27² − 13².
  17. 17.Use a² − b² = (a + b)(a − b) to find 88² − 42².
  18. 18.If a − b = 1 and ab = 72, what is a² + b²?
  19. 19.Use (a − b)² = a² − 2ab + b² to find 91².
  20. 20.Use (a + b)(a − b) = a² − b² to find 72 × 68.
  21. 21.Use (a + b)(a − b) = a² − b² to find 57 × 43.
  22. 22.Use a² − b² = (a + b)(a − b) to find 45² − 39².
  23. 23.If a + b = 5 and ab = 4, what is a² + b²?
  24. 24.Use (a + b)(a − b) = a² − b² to find 77 × 63.
  25. 25.Use (a + b)(a − b) = a² − b² to find 35 × 25.
  26. 26.Find the value of x² + 2xy + y² when x = 7 and y = 1.
  27. 27.Use (a − b)² = a² − 2ab + b² to find 22².
  28. 28.If a − b = 5 and ab = 84, what is a² + b²?
  29. 29.Use a² − b² = (a + b)(a − b) to find 34² − 18².
  30. 30.Use (a + b)² = a² + 2ab + b² to find 28².
  31. 31.If a − b = 5 and ab = 6, what is a² + b²?
  32. 32.If a + b = 10 and ab = 21, what is a² + b²?
  33. 33.Use (a + b)² = a² + 2ab + b² to find 83².
  34. 34.Use (a − b)² = a² − 2ab + b² to find 16².
  35. 35.Use (a + b)(a − b) = a² − b² to find 25 × 15.
  36. 36.Use (a − b)² = a² − 2ab + b² to find 87².
  37. 37.Use (a + b)(a − b) = a² − b² to find 48 × 32.
  38. 38.Use (a − b)² = a² − 2ab + b² to find 81².
  39. 39.Use a² − b² = (a + b)(a − b) to find 52² − 25².
  40. 40.Use (a − b)² = a² − 2ab + b² to find 57².

Answer key

  1. 120
  2. 2793
  3. 5
  4. 1296
  5. 289
  6. 1664
  7. 399
  8. 10
  9. 137
  10. 4
  11. 1853
  12. 52
  13. 484
  14. 64
  15. 361
  16. 560
  17. 5980
  18. 145
  19. 8281
  20. 4896
  21. 2451
  22. 504
  23. 17
  24. 4851
  25. 875
  26. 64
  27. 484
  28. 193
  29. 832
  30. 784
  31. 37
  32. 58
  33. 6889
  34. 256
  35. 375
  36. 7569
  37. 1536
  38. 6561
  39. 2079
  40. 3249

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