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Class 8 Maths Worksheet: Algebraic Identities

Maths worksheets lesson 61: Algebraic identities · Set 848 · 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 83².
  2. 2.Find the value of x² − y² when x = 10 and y = 2.
  3. 3.Use (a − b)² = a² − 2ab + b² to find 73².
  4. 4.Use (a + b)(a − b) = a² − b² to find 48 × 32.
  5. 5.Use (a − b)² = a² − 2ab + b² to find 97².
  6. 6.Use (a + b)² = a² + 2ab + b² to find 57².
  7. 7.Use (a − b)² = a² − 2ab + b² to find 72².
  8. 8.If a + b = 10 and ab = 9, what is a² + b²?
  9. 9.Use (a + b)² = a² + 2ab + b² to find 82².
  10. 10.If a + b = 18 and ab = 77, what is a² + b²?
  11. 11.Find the value of x² + 2xy + y² when x = 4 and y = 3.
  12. 12.Use a² − b² = (a + b)(a − b) to find 23² − 8².
  13. 13.Use (a − b)² = a² − 2ab + b² to find 27².
  14. 14.Use (a + b)² = a² + 2ab + b² to find 91².
  15. 15.Use (a + b)² = a² + 2ab + b² to find 32².
  16. 16.Use (a + b)(a − b) = a² − b² to find 43 × 37.
  17. 17.Use (a + b)² = a² + 2ab + b² to find 94².
  18. 18.Use (a + b)(a − b) = a² − b² to find 71 × 69.
  19. 19.Use (a + b)² = a² + 2ab + b² to find 37².
  20. 20.Use (a + b)² = a² + 2ab + b² to find 41².
  21. 21.Use (a + b)² = a² + 2ab + b² to find 76².
  22. 22.Use (a − b)² = a² − 2ab + b² to find 18².
  23. 23.Use (a + b)² = a² + 2ab + b² to find 97².
  24. 24.Use (a + b)(a − b) = a² − b² to find 93 × 87.
  25. 25.If a + b = 20 and ab = 99, what is a² + b²?
  26. 26.Use a² − b² = (a + b)(a − b) to find 54² − 44².
  27. 27.Use (a + b)² = a² + 2ab + b² to find 64².
  28. 28.Use a² − b² = (a + b)(a − b) to find 27² − 20².
  29. 29.Find the value of x² + 2xy + y² when x = 4 and y = 2.
  30. 30.Use (a + b)² = a² + 2ab + b² to find 12².
  31. 31.Use (a + b)(a − b) = a² − b² to find 105 × 95.
  32. 32.Use a² − b² = (a + b)(a − b) to find 54² − 29².
  33. 33.If a − b = 1 and ab = 6, what is a² + b²?
  34. 34.Find the value of x² − 2xy + y² when x = 5 and y = 1.
  35. 35.If a − b = 3 and ab = 18, what is a² + b²?
  36. 36.If a + b = 13 and ab = 36, what is a² + b²?
  37. 37.Use (a + b)² = a² + 2ab + b² to find 46².
  38. 38.Use (a − b)² = a² − 2ab + b² to find 45².
  39. 39.Use (a + b)(a − b) = a² − b² to find 91 × 89.
  40. 40.If a − b = 4 and ab = 45, what is a² + b²?

Answer key

  1. 6889
  2. 96
  3. 5329
  4. 1536
  5. 9409
  6. 3249
  7. 5184
  8. 82
  9. 6724
  10. 170
  11. 49
  12. 465
  13. 729
  14. 8281
  15. 1024
  16. 1591
  17. 8836
  18. 4899
  19. 1369
  20. 1681
  21. 5776
  22. 324
  23. 9409
  24. 8091
  25. 202
  26. 980
  27. 4096
  28. 329
  29. 36
  30. 144
  31. 9975
  32. 2075
  33. 13
  34. 16
  35. 45
  36. 97
  37. 2116
  38. 2025
  39. 8099
  40. 106

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