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Class 8 Maths Worksheet: Algebraic Identities

Maths worksheets lesson 61: Algebraic identities · Set 890 · 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 77².
  2. 2.Use (a + b)² = a² + 2ab + b² to find 63².
  3. 3.Use a² − b² = (a + b)(a − b) to find 89² − 79².
  4. 4.Use (a − b)² = a² − 2ab + b² to find 89².
  5. 5.Use a² − b² = (a + b)(a − b) to find 65² − 33².
  6. 6.Use a² − b² = (a + b)(a − b) to find 67² − 26².
  7. 7.Use (a − b)² = a² − 2ab + b² to find 59².
  8. 8.If a − b = 10 and ab = 11, what is a² + b²?
  9. 9.Use a² − b² = (a + b)(a − b) to find 22² − 10².
  10. 10.Use (a + b)² = a² + 2ab + b² to find 17².
  11. 11.Use a² − b² = (a + b)(a − b) to find 62² − 46².
  12. 12.If a + b = 5 and ab = 6, what is a² + b²?
  13. 13.If a + b = 11 and ab = 30, what is a² + b²?
  14. 14.Use (a + b)² = a² + 2ab + b² to find 108².
  15. 15.Use (a + b)(a − b) = a² − b² to find 105 × 95.
  16. 16.If a + b = 3 and ab = 2, what is a² + b²?
  17. 17.Use a² − b² = (a + b)(a − b) to find 96² − 51².
  18. 18.Find the value of x² + 2xy + y² when x = 11 and y = 4.
  19. 19.Use (a + b)² = a² + 2ab + b² to find 43².
  20. 20.Use (a − b)² = a² − 2ab + b² to find 43².
  21. 21.Use (a + b)(a − b) = a² − b² to find 72 × 68.
  22. 22.Use (a + b)² = a² + 2ab + b² to find 34².
  23. 23.Find the value of x² − 2xy + y² when x = 7 and y = 6.
  24. 24.Use (a − b)² = a² − 2ab + b² to find 31².
  25. 25.Use a² − b² = (a + b)(a − b) to find 99² − 33².
  26. 26.Find the value of x² − 2xy + y² when x = 3 and y = 1.
  27. 27.Use (a − b)² = a² − 2ab + b² to find 26².
  28. 28.Use (a − b)² = a² − 2ab + b² to find 84².
  29. 29.Use (a + b)² = a² + 2ab + b² to find 65².
  30. 30.Use (a + b)(a − b) = a² − b² to find 44 × 36.
  31. 31.Use (a − b)² = a² − 2ab + b² to find 35².
  32. 32.Find the value of x² − 2xy + y² when x = 14 and y = 12.
  33. 33.If a + b = 8 and ab = 12, what is a² + b²?
  34. 34.Find the value of x² − 2xy + y² when x = 13 and y = 6.
  35. 35.Use (a − b)² = a² − 2ab + b² to find 83².
  36. 36.Use a² − b² = (a + b)(a − b) to find 47² − 16².
  37. 37.Use (a + b)² = a² + 2ab + b² to find 57².
  38. 38.Find the value of x² − 2xy + y² when x = 13 and y = 9.
  39. 39.If a + b = 20 and ab = 96, what is a² + b²?
  40. 40.If a + b = 21 and ab = 110, what is a² + b²?

Answer key

  1. 5929
  2. 3969
  3. 1680
  4. 7921
  5. 3136
  6. 3813
  7. 3481
  8. 122
  9. 384
  10. 289
  11. 1728
  12. 13
  13. 61
  14. 11664
  15. 9975
  16. 5
  17. 6615
  18. 225
  19. 1849
  20. 1849
  21. 4896
  22. 1156
  23. 1
  24. 961
  25. 8712
  26. 4
  27. 676
  28. 7056
  29. 4225
  30. 1584
  31. 1225
  32. 4
  33. 40
  34. 49
  35. 6889
  36. 1953
  37. 3249
  38. 16
  39. 208
  40. 221

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