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Class 8 Maths Worksheet: Algebraic Identities

Maths worksheets lesson 61: Algebraic identities · Set 965 · 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)(a − b) = a² − b² to find 107 × 93.
  2. 2.Use (a − b)² = a² − 2ab + b² to find 46².
  3. 3.Use (a − b)² = a² − 2ab + b² to find 36².
  4. 4.If a + b = 3 and ab = 2, what is a² + b²?
  5. 5.Use a² − b² = (a + b)(a − b) to find 21² − 11².
  6. 6.If a − b = 1 and ab = 2, what is a² + b²?
  7. 7.Use (a + b)² = a² + 2ab + b² to find 22².
  8. 8.Use (a + b)(a − b) = a² − b² to find 33 × 27.
  9. 9.Use (a + b)² = a² + 2ab + b² to find 52².
  10. 10.Use (a + b)² = a² + 2ab + b² to find 95².
  11. 11.Use a² − b² = (a + b)(a − b) to find 56² − 1².
  12. 12.Find the value of x² + 2xy + y² when x = 5 and y = 3.
  13. 13.Use a² − b² = (a + b)(a − b) to find 84² − 18².
  14. 14.Use (a + b)(a − b) = a² − b² to find 62 × 58.
  15. 15.Use (a − b)² = a² − 2ab + b² to find 32².
  16. 16.Use (a + b)(a − b) = a² − b² to find 37 × 23.
  17. 17.Use a² − b² = (a + b)(a − b) to find 86² − 33².
  18. 18.Use (a + b)(a − b) = a² − b² to find 101 × 99.
  19. 19.Find the value of x² − 2xy + y² when x = 4 and y = 3.
  20. 20.If a − b = 10 and ab = 11, what is a² + b²?
  21. 21.Find the value of x² − 2xy + y² when x = 11 and y = 4.
  22. 22.Use (a − b)² = a² − 2ab + b² to find 86².
  23. 23.Find the value of x² − y² when x = 10 and y = 5.
  24. 24.If a − b = 6 and ab = 27, what is a² + b²?
  25. 25.Use (a − b)² = a² − 2ab + b² to find 17².
  26. 26.Use a² − b² = (a + b)(a − b) to find 57² − 15².
  27. 27.Find the value of x² − y² when x = 12 and y = 5.
  28. 28.Find the value of x² − y² when x = 5 and y = 4.
  29. 29.If a + b = 8 and ab = 12, what is a² + b²?
  30. 30.Find the value of x² − y² when x = 4 and y = 3.
  31. 31.Use (a + b)(a − b) = a² − b² to find 31 × 29.
  32. 32.Use (a − b)² = a² − 2ab + b² to find 34².
  33. 33.Use (a + b)² = a² + 2ab + b² to find 104².
  34. 34.Use (a + b)² = a² + 2ab + b² to find 13².
  35. 35.Use (a − b)² = a² − 2ab + b² to find 71².
  36. 36.Find the value of x² − 2xy + y² when x = 10 and y = 3.
  37. 37.Use (a − b)² = a² − 2ab + b² to find 76².
  38. 38.Use (a − b)² = a² − 2ab + b² to find 98².
  39. 39.Use (a − b)² = a² − 2ab + b² to find 93².
  40. 40.Use (a + b)² = a² + 2ab + b² to find 14².

Answer key

  1. 9951
  2. 2116
  3. 1296
  4. 5
  5. 320
  6. 5
  7. 484
  8. 891
  9. 2704
  10. 9025
  11. 3135
  12. 64
  13. 6732
  14. 3596
  15. 1024
  16. 851
  17. 6307
  18. 9999
  19. 1
  20. 122
  21. 49
  22. 7396
  23. 75
  24. 90
  25. 289
  26. 3024
  27. 119
  28. 9
  29. 40
  30. 7
  31. 899
  32. 1156
  33. 10816
  34. 169
  35. 5041
  36. 49
  37. 5776
  38. 9604
  39. 8649
  40. 196

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