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Class 8 Maths Worksheet: Algebraic Identities

Maths worksheets lesson 61: Algebraic identities · Set 579 · 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.Use (a − b)² = a² − 2ab + b² to find 26².
  2. 2.Use (a + b)² = a² + 2ab + b² to find 101².
  3. 3.Find the value of x² − y² when x = 8 and y = 1.
  4. 4.Use a² − b² = (a + b)(a − b) to find 93² − 8².
  5. 5.Use (a + b)(a − b) = a² − b² to find 94 × 86.
  6. 6.Use (a + b)² = a² + 2ab + b² to find 83².
  7. 7.Use (a + b)(a − b) = a² − b² to find 23 × 17.
  8. 8.Find the value of x² − y² when x = 13 and y = 3.
  9. 9.Use (a − b)² = a² − 2ab + b² to find 19².
  10. 10.Use a² − b² = (a + b)(a − b) to find 64² − 52².
  11. 11.Use (a + b)² = a² + 2ab + b² to find 13².
  12. 12.If a − b = 2 and ab = 35, what is a² + b²?
  13. 13.Find the value of x² − y² when x = 4 and y = 2.
  14. 14.If a + b = 5 and ab = 6, what is a² + b²?
  15. 15.Find the value of x² − 2xy + y² when x = 5 and y = 3.
  16. 16.Use a² − b² = (a + b)(a − b) to find 73² − 22².
  17. 17.Use a² − b² = (a + b)(a − b) to find 90² − 44².
  18. 18.Use (a + b)² = a² + 2ab + b² to find 25².
  19. 19.Use (a + b)(a − b) = a² − b² to find 76 × 64.
  20. 20.Use (a − b)² = a² − 2ab + b² to find 51².
  21. 21.Use (a + b)(a − b) = a² − b² to find 56 × 44.
  22. 22.Find the value of x² − 2xy + y² when x = 5 and y = 4.
  23. 23.Use (a + b)² = a² + 2ab + b² to find 67².
  24. 24.Find the value of x² + 2xy + y² when x = 10 and y = 5.
  25. 25.If a + b = 13 and ab = 40, what is a² + b²?
  26. 26.Find the value of x² + 2xy + y² when x = 3 and y = 2.
  27. 27.If a − b = 9 and ab = 10, what is a² + b²?
  28. 28.Use a² − b² = (a + b)(a − b) to find 71² − 60².
  29. 29.Use a² − b² = (a + b)(a − b) to find 30² − 24².
  30. 30.Use a² − b² = (a + b)(a − b) to find 91² − 80².
  31. 31.Use (a − b)² = a² − 2ab + b² to find 93².
  32. 32.If a − b = 3 and ab = 28, what is a² + b²?
  33. 33.Use a² − b² = (a + b)(a − b) to find 36² − 8².
  34. 34.If a + b = 9 and ab = 14, what is a² + b²?
  35. 35.Find the value of x² − 2xy + y² when x = 12 and y = 7.
  36. 36.If a − b = 7 and ab = 30, what is a² + b²?
  37. 37.Find the value of x² + 2xy + y² when x = 13 and y = 2.
  38. 38.Use a² − b² = (a + b)(a − b) to find 33² − 17².
  39. 39.Use (a − b)² = a² − 2ab + b² to find 72².
  40. 40.Find the value of x² + 2xy + y² when x = 15 and y = 2.

Answer key

  1. 676
  2. 10201
  3. 63
  4. 8585
  5. 8084
  6. 6889
  7. 391
  8. 160
  9. 361
  10. 1392
  11. 169
  12. 74
  13. 12
  14. 13
  15. 4
  16. 4845
  17. 6164
  18. 625
  19. 4864
  20. 2601
  21. 2464
  22. 1
  23. 4489
  24. 225
  25. 89
  26. 25
  27. 101
  28. 1441
  29. 324
  30. 1881
  31. 8649
  32. 65
  33. 1232
  34. 53
  35. 25
  36. 109
  37. 225
  38. 800
  39. 5184
  40. 289

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