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Class 8 Maths Worksheet: Algebraic Identities

Maths worksheets lesson 61: Algebraic identities · Set 444 · 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.Find the value of x² − y² when x = 3 and y = 1.
  2. 2.Use a² − b² = (a + b)(a − b) to find 50² − 4².
  3. 3.If a + b = 17 and ab = 66, what is a² + b²?
  4. 4.If a − b = 1 and ab = 2, what is a² + b²?
  5. 5.Find the value of x² − 2xy + y² when x = 6 and y = 2.
  6. 6.If a − b = 5 and ab = 6, what is a² + b²?
  7. 7.Use (a + b)(a − b) = a² − b² to find 22 × 18.
  8. 8.Use (a − b)² = a² − 2ab + b² to find 69².
  9. 9.If a + b = 6 and ab = 5, what is a² + b²?
  10. 10.Use (a + b)² = a² + 2ab + b² to find 102².
  11. 11.Use (a + b)² = a² + 2ab + b² to find 103².
  12. 12.Use a² − b² = (a + b)(a − b) to find 83² − 51².
  13. 13.Use (a − b)² = a² − 2ab + b² to find 31².
  14. 14.Find the value of x² − 2xy + y² when x = 11 and y = 9.
  15. 15.Use (a + b)(a − b) = a² − b² to find 32 × 28.
  16. 16.Use (a + b)² = a² + 2ab + b² to find 46².
  17. 17.Use a² − b² = (a + b)(a − b) to find 76² − 43².
  18. 18.Find the value of x² − y² when x = 5 and y = 1.
  19. 19.Use (a − b)² = a² − 2ab + b² to find 74².
  20. 20.Use (a + b)(a − b) = a² − b² to find 72 × 68.
  21. 21.Use (a + b)² = a² + 2ab + b² to find 92².
  22. 22.Use (a + b)(a − b) = a² − b² to find 59 × 41.
  23. 23.Find the value of x² + 2xy + y² when x = 4 and y = 1.
  24. 24.If a + b = 15 and ab = 44, what is a² + b²?
  25. 25.Find the value of x² + 2xy + y² when x = 7 and y = 5.
  26. 26.Use a² − b² = (a + b)(a − b) to find 33² − 12².
  27. 27.Use (a + b)(a − b) = a² − b² to find 33 × 27.
  28. 28.Use (a + b)² = a² + 2ab + b² to find 25².
  29. 29.Use (a + b)(a − b) = a² − b² to find 26 × 14.
  30. 30.Use (a + b)(a − b) = a² − b² to find 42 × 38.
  31. 31.Use (a − b)² = a² − 2ab + b² to find 34².
  32. 32.Find the value of x² − y² when x = 6 and y = 2.
  33. 33.Use (a + b)² = a² + 2ab + b² to find 58².
  34. 34.Use (a + b)² = a² + 2ab + b² to find 77².
  35. 35.Use (a + b)² = a² + 2ab + b² to find 88².
  36. 36.Use (a + b)(a − b) = a² − b² to find 34 × 26.
  37. 37.If a + b = 14 and ab = 40, what is a² + b²?
  38. 38.If a − b = 2 and ab = 3, what is a² + b²?
  39. 39.If a + b = 7 and ab = 12, what is a² + b²?
  40. 40.Use (a + b)² = a² + 2ab + b² to find 22².

Answer key

  1. 8
  2. 2484
  3. 157
  4. 5
  5. 16
  6. 37
  7. 396
  8. 4761
  9. 26
  10. 10404
  11. 10609
  12. 4288
  13. 961
  14. 4
  15. 896
  16. 2116
  17. 3927
  18. 24
  19. 5476
  20. 4896
  21. 8464
  22. 2419
  23. 25
  24. 137
  25. 144
  26. 945
  27. 891
  28. 625
  29. 364
  30. 1596
  31. 1156
  32. 32
  33. 3364
  34. 5929
  35. 7744
  36. 884
  37. 116
  38. 10
  39. 25
  40. 484

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