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Class 8 Maths Worksheet: Algebraic Identities

Maths worksheets lesson 61: Algebraic identities · Set 936 · 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 27².
  2. 2.Use a² − b² = (a + b)(a − b) to find 97² − 88².
  3. 3.If a − b = 3 and ab = 10, what is a² + b²?
  4. 4.Use (a − b)² = a² − 2ab + b² to find 72².
  5. 5.Use a² − b² = (a + b)(a − b) to find 97² − 9².
  6. 6.Use a² − b² = (a + b)(a − b) to find 57² − 14².
  7. 7.Use a² − b² = (a + b)(a − b) to find 34² − 20².
  8. 8.Find the value of x² − y² when x = 14 and y = 2.
  9. 9.Use (a − b)² = a² − 2ab + b² to find 84².
  10. 10.Find the value of x² − 2xy + y² when x = 5 and y = 1.
  11. 11.Use (a − b)² = a² − 2ab + b² to find 12².
  12. 12.Use (a + b)² = a² + 2ab + b² to find 58².
  13. 13.Use (a − b)² = a² − 2ab + b² to find 53².
  14. 14.If a − b = 7 and ab = 18, what is a² + b²?
  15. 15.Find the value of x² + 2xy + y² when x = 11 and y = 1.
  16. 16.Use a² − b² = (a + b)(a − b) to find 33² − 15².
  17. 17.Find the value of x² − 2xy + y² when x = 9 and y = 2.
  18. 18.Use a² − b² = (a + b)(a − b) to find 48² − 17².
  19. 19.Use (a − b)² = a² − 2ab + b² to find 54².
  20. 20.Use (a − b)² = a² − 2ab + b² to find 18².
  21. 21.Find the value of x² − 2xy + y² when x = 15 and y = 1.
  22. 22.If a + b = 20 and ab = 96, what is a² + b²?
  23. 23.Use (a + b)(a − b) = a² − b² to find 71 × 69.
  24. 24.If a − b = 1 and ab = 2, what is a² + b²?
  25. 25.Use a² − b² = (a + b)(a − b) to find 73² − 9².
  26. 26.Use (a + b)² = a² + 2ab + b² to find 16².
  27. 27.Use (a + b)² = a² + 2ab + b² to find 106².
  28. 28.If a − b = 6 and ab = 16, what is a² + b²?
  29. 29.Use (a − b)² = a² − 2ab + b² to find 16².
  30. 30.Use a² − b² = (a + b)(a − b) to find 89² − 21².
  31. 31.Use (a − b)² = a² − 2ab + b² to find 56².
  32. 32.Find the value of x² − y² when x = 12 and y = 11.
  33. 33.Use (a − b)² = a² − 2ab + b² to find 88².
  34. 34.Use (a − b)² = a² − 2ab + b² to find 58².
  35. 35.If a − b = 9 and ab = 36, what is a² + b²?
  36. 36.Use (a − b)² = a² − 2ab + b² to find 38².
  37. 37.Use (a + b)² = a² + 2ab + b² to find 56².
  38. 38.Use a² − b² = (a + b)(a − b) to find 25² − 24².
  39. 39.Use a² − b² = (a + b)(a − b) to find 90² − 52².
  40. 40.Use a² − b² = (a + b)(a − b) to find 61² − 53².

Answer key

  1. 729
  2. 1665
  3. 29
  4. 5184
  5. 9328
  6. 3053
  7. 756
  8. 192
  9. 7056
  10. 16
  11. 144
  12. 3364
  13. 2809
  14. 85
  15. 144
  16. 864
  17. 49
  18. 2015
  19. 2916
  20. 324
  21. 196
  22. 208
  23. 4899
  24. 5
  25. 5248
  26. 256
  27. 11236
  28. 68
  29. 256
  30. 7480
  31. 3136
  32. 23
  33. 7744
  34. 3364
  35. 153
  36. 1444
  37. 3136
  38. 49
  39. 5396
  40. 912

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