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Class 8 Maths Worksheet: Algebraic Identities

Maths worksheets lesson 61: Algebraic identities · Set 414 · 40 sums
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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 58².
  2. 2.Use (a + b)² = a² + 2ab + b² to find 42².
  3. 3.Find the value of x² − y² when x = 11 and y = 9.
  4. 4.Use (a + b)² = a² + 2ab + b² to find 29².
  5. 5.Use (a − b)² = a² − 2ab + b² to find 88².
  6. 6.Find the value of x² − 2xy + y² when x = 5 and y = 4.
  7. 7.Use (a + b)² = a² + 2ab + b² to find 96².
  8. 8.Use (a + b)² = a² + 2ab + b² to find 106².
  9. 9.Use a² − b² = (a + b)(a − b) to find 57² − 24².
  10. 10.Find the value of x² − y² when x = 3 and y = 2.
  11. 11.Use (a − b)² = a² − 2ab + b² to find 99².
  12. 12.Use (a − b)² = a² − 2ab + b² to find 85².
  13. 13.Use (a + b)(a − b) = a² − b² to find 84 × 76.
  14. 14.Use (a + b)(a − b) = a² − b² to find 58 × 42.
  15. 15.Find the value of x² + 2xy + y² when x = 5 and y = 1.
  16. 16.Use (a − b)² = a² − 2ab + b² to find 31².
  17. 17.Use (a + b)(a − b) = a² − b² to find 102 × 98.
  18. 18.Use a² − b² = (a + b)(a − b) to find 38² − 16².
  19. 19.Use (a − b)² = a² − 2ab + b² to find 94².
  20. 20.Use a² − b² = (a + b)(a − b) to find 39² − 34².
  21. 21.Find the value of x² − 2xy + y² when x = 10 and y = 1.
  22. 22.If a − b = 1 and ab = 2, what is a² + b²?
  23. 23.If a + b = 19 and ab = 88, what is a² + b²?
  24. 24.Find the value of x² − 2xy + y² when x = 14 and y = 11.
  25. 25.Use (a + b)(a − b) = a² − b² to find 61 × 59.
  26. 26.Use (a − b)² = a² − 2ab + b² to find 54².
  27. 27.Use (a − b)² = a² − 2ab + b² to find 67².
  28. 28.Use (a + b)² = a² + 2ab + b² to find 105².
  29. 29.Use (a + b)(a − b) = a² − b² to find 91 × 89.
  30. 30.Use (a + b)(a − b) = a² − b² to find 41 × 39.
  31. 31.Find the value of x² − 2xy + y² when x = 6 and y = 4.
  32. 32.Use a² − b² = (a + b)(a − b) to find 23² − 5².
  33. 33.Use (a + b)² = a² + 2ab + b² to find 102².
  34. 34.Use (a + b)² = a² + 2ab + b² to find 76².
  35. 35.If a − b = 9 and ab = 10, what is a² + b²?
  36. 36.Use (a + b)(a − b) = a² − b² to find 97 × 83.
  37. 37.Find the value of x² − 2xy + y² when x = 8 and y = 5.
  38. 38.Find the value of x² + 2xy + y² when x = 6 and y = 2.
  39. 39.Use a² − b² = (a + b)(a − b) to find 44² − 13².
  40. 40.Use (a + b)(a − b) = a² − b² to find 52 × 48.

Answer key

  1. 3364
  2. 1764
  3. 40
  4. 841
  5. 7744
  6. 1
  7. 9216
  8. 11236
  9. 2673
  10. 5
  11. 9801
  12. 7225
  13. 6384
  14. 2436
  15. 36
  16. 961
  17. 9996
  18. 1188
  19. 8836
  20. 365
  21. 81
  22. 5
  23. 185
  24. 9
  25. 3599
  26. 2916
  27. 4489
  28. 11025
  29. 8099
  30. 1599
  31. 4
  32. 504
  33. 10404
  34. 5776
  35. 101
  36. 8051
  37. 9
  38. 64
  39. 1767
  40. 2496

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