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Class 8 Maths Worksheet: Algebraic Identities

Maths worksheets lesson 61: Algebraic identities · Set 67 · 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.Find the value of x² + 2xy + y² when x = 5 and y = 1.
  2. 2.Use a² − b² = (a + b)(a − b) to find 34² − 16².
  3. 3.Use (a − b)² = a² − 2ab + b² to find 36².
  4. 4.Use (a + b)² = a² + 2ab + b² to find 17².
  5. 5.Use (a − b)² = a² − 2ab + b² to find 64².
  6. 6.Use (a + b)(a − b) = a² − b² to find 57 × 43.
  7. 7.Use (a + b)(a − b) = a² − b² to find 88 × 72.
  8. 8.Use (a + b)(a − b) = a² − b² to find 105 × 95.
  9. 9.Use (a + b)² = a² + 2ab + b² to find 72².
  10. 10.Use (a − b)² = a² − 2ab + b² to find 19².
  11. 11.Use (a + b)² = a² + 2ab + b² to find 88².
  12. 12.Use a² − b² = (a + b)(a − b) to find 37² − 6².
  13. 13.Use (a + b)² = a² + 2ab + b² to find 105².
  14. 14.Use (a + b)(a − b) = a² − b² to find 83 × 77.
  15. 15.Use (a + b)(a − b) = a² − b² to find 36 × 24.
  16. 16.If a − b = 2 and ab = 48, what is a² + b²?
  17. 17.Use a² − b² = (a + b)(a − b) to find 35² − 20².
  18. 18.Use (a − b)² = a² − 2ab + b² to find 16².
  19. 19.Use (a + b)² = a² + 2ab + b² to find 64².
  20. 20.Use a² − b² = (a + b)(a − b) to find 24² − 4².
  21. 21.Use a² − b² = (a + b)(a − b) to find 69² − 54².
  22. 22.Use (a − b)² = a² − 2ab + b² to find 14².
  23. 23.Use (a + b)² = a² + 2ab + b² to find 83².
  24. 24.Use (a − b)² = a² − 2ab + b² to find 77².
  25. 25.If a − b = 1 and ab = 2, what is a² + b²?
  26. 26.Use (a − b)² = a² − 2ab + b² to find 33².
  27. 27.Use (a + b)(a − b) = a² − b² to find 47 × 33.
  28. 28.Use (a − b)² = a² − 2ab + b² to find 78².
  29. 29.Use (a + b)² = a² + 2ab + b² to find 95².
  30. 30.Use (a − b)² = a² − 2ab + b² to find 43².
  31. 31.Use (a − b)² = a² − 2ab + b² to find 49².
  32. 32.Use (a − b)² = a² − 2ab + b² to find 39².
  33. 33.Use (a + b)² = a² + 2ab + b² to find 85².
  34. 34.Use a² − b² = (a + b)(a − b) to find 32² − 11².
  35. 35.If a − b = 5 and ab = 6, what is a² + b²?
  36. 36.Use (a − b)² = a² − 2ab + b² to find 99².
  37. 37.Use a² − b² = (a + b)(a − b) to find 63² − 54².
  38. 38.If a + b = 3 and ab = 2, what is a² + b²?
  39. 39.Use a² − b² = (a + b)(a − b) to find 61² − 28².
  40. 40.Use (a + b)(a − b) = a² − b² to find 44 × 36.

Answer key

  1. 36
  2. 900
  3. 1296
  4. 289
  5. 4096
  6. 2451
  7. 6336
  8. 9975
  9. 5184
  10. 361
  11. 7744
  12. 1333
  13. 11025
  14. 6391
  15. 864
  16. 100
  17. 825
  18. 256
  19. 4096
  20. 560
  21. 1845
  22. 196
  23. 6889
  24. 5929
  25. 5
  26. 1089
  27. 1551
  28. 6084
  29. 9025
  30. 1849
  31. 2401
  32. 1521
  33. 7225
  34. 903
  35. 37
  36. 9801
  37. 1053
  38. 5
  39. 2937
  40. 1584

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