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Class 8 Maths Worksheet: Algebraic Identities

Maths worksheets lesson 61: Algebraic identities · Set 699 · 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)(a − b) = a² − b² to find 103 × 97.
  2. 2.Use (a − b)² = a² − 2ab + b² to find 19².
  3. 3.Find the value of x² − 2xy + y² when x = 8 and y = 2.
  4. 4.Use (a + b)² = a² + 2ab + b² to find 61².
  5. 5.Find the value of x² − 2xy + y² when x = 10 and y = 3.
  6. 6.Use a² − b² = (a + b)(a − b) to find 78² − 16².
  7. 7.Find the value of x² − y² when x = 11 and y = 1.
  8. 8.Find the value of x² + 2xy + y² when x = 8 and y = 1.
  9. 9.Use (a + b)² = a² + 2ab + b² to find 21².
  10. 10.If a − b = 3 and ab = 10, what is a² + b²?
  11. 11.Use (a + b)² = a² + 2ab + b² to find 12².
  12. 12.Use (a + b)² = a² + 2ab + b² to find 26².
  13. 13.Use (a + b)² = a² + 2ab + b² to find 22².
  14. 14.Find the value of x² − 2xy + y² when x = 12 and y = 6.
  15. 15.Use (a + b)² = a² + 2ab + b² to find 81².
  16. 16.Use a² − b² = (a + b)(a − b) to find 73² − 30².
  17. 17.Use (a + b)(a − b) = a² − b² to find 107 × 93.
  18. 18.Find the value of x² − y² when x = 8 and y = 2.
  19. 19.Use (a − b)² = a² − 2ab + b² to find 55².
  20. 20.Use a² − b² = (a + b)(a − b) to find 52² − 5².
  21. 21.Use (a + b)(a − b) = a² − b² to find 57 × 43.
  22. 22.Use a² − b² = (a + b)(a − b) to find 64² − 49².
  23. 23.Use (a + b)² = a² + 2ab + b² to find 42².
  24. 24.If a − b = 4 and ab = 96, what is a² + b²?
  25. 25.Find the value of x² + 2xy + y² when x = 7 and y = 2.
  26. 26.Find the value of x² + 2xy + y² when x = 4 and y = 2.
  27. 27.Find the value of x² + 2xy + y² when x = 7 and y = 4.
  28. 28.Use a² − b² = (a + b)(a − b) to find 37² − 3².
  29. 29.Use a² − b² = (a + b)(a − b) to find 30² − 15².
  30. 30.Use (a − b)² = a² − 2ab + b² to find 34².
  31. 31.Use (a + b)(a − b) = a² − b² to find 34 × 26.
  32. 32.Use (a + b)² = a² + 2ab + b² to find 45².
  33. 33.Use a² − b² = (a + b)(a − b) to find 70² − 63².
  34. 34.Use (a + b)² = a² + 2ab + b² to find 38².
  35. 35.Use (a + b)² = a² + 2ab + b² to find 24².
  36. 36.Use (a − b)² = a² − 2ab + b² to find 42².
  37. 37.Use (a + b)(a − b) = a² − b² to find 46 × 34.
  38. 38.Use (a + b)(a − b) = a² − b² to find 84 × 76.
  39. 39.Find the value of x² − 2xy + y² when x = 6 and y = 4.
  40. 40.Use (a + b)(a − b) = a² − b² to find 35 × 25.

Answer key

  1. 9991
  2. 361
  3. 36
  4. 3721
  5. 49
  6. 5828
  7. 120
  8. 81
  9. 441
  10. 29
  11. 144
  12. 676
  13. 484
  14. 36
  15. 6561
  16. 4429
  17. 9951
  18. 60
  19. 3025
  20. 2679
  21. 2451
  22. 1695
  23. 1764
  24. 208
  25. 81
  26. 36
  27. 121
  28. 1360
  29. 675
  30. 1156
  31. 884
  32. 2025
  33. 931
  34. 1444
  35. 576
  36. 1764
  37. 1564
  38. 6384
  39. 4
  40. 875

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