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Class 8 Maths Worksheet: Algebraic Identities

Maths worksheets lesson 61: Algebraic identities · Set 662 · 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.If a + b = 19 and ab = 84, what is a² + b²?
  2. 2.Find the value of x² − 2xy + y² when x = 6 and y = 1.
  3. 3.Use a² − b² = (a + b)(a − b) to find 24² − 17².
  4. 4.Use (a + b)(a − b) = a² − b² to find 27 × 13.
  5. 5.If a − b = 9 and ab = 36, what is a² + b²?
  6. 6.Use (a + b)² = a² + 2ab + b² to find 106².
  7. 7.Use (a − b)² = a² − 2ab + b² to find 55².
  8. 8.Use (a + b)(a − b) = a² − b² to find 106 × 94.
  9. 9.Use (a + b)² = a² + 2ab + b² to find 52².
  10. 10.Find the value of x² + 2xy + y² when x = 9 and y = 8.
  11. 11.Use a² − b² = (a + b)(a − b) to find 81² − 57².
  12. 12.Use (a − b)² = a² − 2ab + b² to find 87².
  13. 13.Use a² − b² = (a + b)(a − b) to find 24² − 22².
  14. 14.Find the value of x² + 2xy + y² when x = 5 and y = 1.
  15. 15.Use (a + b)(a − b) = a² − b² to find 33 × 27.
  16. 16.Use (a + b)(a − b) = a² − b² to find 66 × 54.
  17. 17.Use (a + b)² = a² + 2ab + b² to find 101².
  18. 18.Use (a − b)² = a² − 2ab + b² to find 53².
  19. 19.Use (a + b)(a − b) = a² − b² to find 24 × 16.
  20. 20.If a − b = 2 and ab = 3, what is a² + b²?
  21. 21.Use (a + b)(a − b) = a² − b² to find 46 × 34.
  22. 22.Use (a + b)² = a² + 2ab + b² to find 74².
  23. 23.Use (a − b)² = a² − 2ab + b² to find 67².
  24. 24.Use (a + b)² = a² + 2ab + b² to find 19².
  25. 25.Use (a − b)² = a² − 2ab + b² to find 94².
  26. 26.If a − b = 8 and ab = 9, what is a² + b²?
  27. 27.Use (a + b)(a − b) = a² − b² to find 69 × 51.
  28. 28.Find the value of x² − y² when x = 7 and y = 1.
  29. 29.Use (a − b)² = a² − 2ab + b² to find 37².
  30. 30.Use (a + b)² = a² + 2ab + b² to find 18².
  31. 31.Use (a + b)² = a² + 2ab + b² to find 83².
  32. 32.Use a² − b² = (a + b)(a − b) to find 82² − 71².
  33. 33.If a − b = 8 and ab = 33, what is a² + b²?
  34. 34.Use (a + b)² = a² + 2ab + b² to find 61².
  35. 35.Use a² − b² = (a + b)(a − b) to find 27² − 8².
  36. 36.Find the value of x² − y² when x = 4 and y = 3.
  37. 37.Find the value of x² + 2xy + y² when x = 5 and y = 3.
  38. 38.Use (a − b)² = a² − 2ab + b² to find 82².
  39. 39.Use (a + b)² = a² + 2ab + b² to find 79².
  40. 40.Find the value of x² − 2xy + y² when x = 14 and y = 13.

Answer key

  1. 193
  2. 25
  3. 287
  4. 351
  5. 153
  6. 11236
  7. 3025
  8. 9964
  9. 2704
  10. 289
  11. 3312
  12. 7569
  13. 92
  14. 36
  15. 891
  16. 3564
  17. 10201
  18. 2809
  19. 384
  20. 10
  21. 1564
  22. 5476
  23. 4489
  24. 361
  25. 8836
  26. 82
  27. 3519
  28. 48
  29. 1369
  30. 324
  31. 6889
  32. 1683
  33. 130
  34. 3721
  35. 665
  36. 7
  37. 64
  38. 6724
  39. 6241
  40. 1

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