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Class 8 Maths Worksheet: Algebraic Identities

Maths worksheets lesson 61: Algebraic identities · Set 658 · 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 + 2xy + y² when x = 4 and y = 3.
  2. 2.Find the value of x² − y² when x = 5 and y = 4.
  3. 3.Use (a − b)² = a² − 2ab + b² to find 31².
  4. 4.Use a² − b² = (a + b)(a − b) to find 88² − 33².
  5. 5.Use (a + b)² = a² + 2ab + b² to find 33².
  6. 6.Find the value of x² − y² when x = 4 and y = 3.
  7. 7.Find the value of x² + 2xy + y² when x = 9 and y = 3.
  8. 8.Use (a + b)(a − b) = a² − b² to find 85 × 75.
  9. 9.Use (a + b)² = a² + 2ab + b² to find 101².
  10. 10.Find the value of x² + 2xy + y² when x = 8 and y = 3.
  11. 11.Use (a + b)(a − b) = a² − b² to find 49 × 31.
  12. 12.Use (a − b)² = a² − 2ab + b² to find 66².
  13. 13.Use (a + b)(a − b) = a² − b² to find 72 × 68.
  14. 14.Use (a − b)² = a² − 2ab + b² to find 87².
  15. 15.Use (a − b)² = a² − 2ab + b² to find 21².
  16. 16.Use (a + b)² = a² + 2ab + b² to find 82².
  17. 17.Use (a + b)(a − b) = a² − b² to find 39 × 21.
  18. 18.If a − b = 3 and ab = 40, what is a² + b²?
  19. 19.Use (a − b)² = a² − 2ab + b² to find 77².
  20. 20.Find the value of x² − y² when x = 7 and y = 4.
  21. 21.Use a² − b² = (a + b)(a − b) to find 41² − 2².
  22. 22.If a − b = 1 and ab = 42, what is a² + b²?
  23. 23.Use (a + b)² = a² + 2ab + b² to find 61².
  24. 24.Use (a + b)(a − b) = a² − b² to find 54 × 46.
  25. 25.Use (a + b)² = a² + 2ab + b² to find 35².
  26. 26.Use (a + b)(a − b) = a² − b² to find 104 × 96.
  27. 27.If a + b = 4 and ab = 3, what is a² + b²?
  28. 28.Use (a + b)(a − b) = a² − b² to find 22 × 18.
  29. 29.Use (a − b)² = a² − 2ab + b² to find 88².
  30. 30.If a + b = 9 and ab = 8, what is a² + b²?
  31. 31.Use (a + b)² = a² + 2ab + b² to find 28².
  32. 32.Find the value of x² + 2xy + y² when x = 9 and y = 8.
  33. 33.Use (a − b)² = a² − 2ab + b² to find 86².
  34. 34.Use (a − b)² = a² − 2ab + b² to find 11².
  35. 35.Use (a + b)(a − b) = a² − b² to find 67 × 53.
  36. 36.If a + b = 11 and ab = 18, what is a² + b²?
  37. 37.Find the value of x² + 2xy + y² when x = 9 and y = 1.
  38. 38.Use (a − b)² = a² − 2ab + b² to find 29².
  39. 39.Use (a − b)² = a² − 2ab + b² to find 96².
  40. 40.Find the value of x² − 2xy + y² when x = 7 and y = 3.

Answer key

  1. 49
  2. 9
  3. 961
  4. 6655
  5. 1089
  6. 7
  7. 144
  8. 6375
  9. 10201
  10. 121
  11. 1519
  12. 4356
  13. 4896
  14. 7569
  15. 441
  16. 6724
  17. 819
  18. 89
  19. 5929
  20. 33
  21. 1677
  22. 85
  23. 3721
  24. 2484
  25. 1225
  26. 9984
  27. 10
  28. 396
  29. 7744
  30. 65
  31. 784
  32. 289
  33. 7396
  34. 121
  35. 3551
  36. 85
  37. 100
  38. 841
  39. 9216
  40. 16

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