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Class 8 Maths Worksheet: Algebraic Identities

Maths worksheets lesson 61: Algebraic identities · Set 928 · 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)² = a² + 2ab + b² to find 104².
  2. 2.Use (a − b)² = a² − 2ab + b² to find 69².
  3. 3.Use (a + b)(a − b) = a² − b² to find 68 × 52.
  4. 4.Use a² − b² = (a + b)(a − b) to find 62² − 14².
  5. 5.Use a² − b² = (a + b)(a − b) to find 68² − 11².
  6. 6.Use (a + b)² = a² + 2ab + b² to find 88².
  7. 7.If a − b = 2 and ab = 120, what is a² + b²?
  8. 8.Use (a + b)(a − b) = a² − b² to find 62 × 58.
  9. 9.Use (a + b)(a − b) = a² − b² to find 34 × 26.
  10. 10.If a − b = 2 and ab = 15, what is a² + b²?
  11. 11.Use (a + b)(a − b) = a² − b² to find 66 × 54.
  12. 12.Find the value of x² − 2xy + y² when x = 5 and y = 1.
  13. 13.Use (a + b)² = a² + 2ab + b² to find 107².
  14. 14.If a + b = 11 and ab = 18, what is a² + b²?
  15. 15.Use a² − b² = (a + b)(a − b) to find 53² − 9².
  16. 16.Use (a + b)(a − b) = a² − b² to find 96 × 84.
  17. 17.If a + b = 7 and ab = 6, what is a² + b²?
  18. 18.Use (a + b)(a − b) = a² − b² to find 35 × 25.
  19. 19.Use a² − b² = (a + b)(a − b) to find 93² − 17².
  20. 20.Find the value of x² − 2xy + y² when x = 10 and y = 6.
  21. 21.Use (a − b)² = a² − 2ab + b² to find 94².
  22. 22.Find the value of x² − 2xy + y² when x = 7 and y = 6.
  23. 23.Use (a − b)² = a² − 2ab + b² to find 78².
  24. 24.Use a² − b² = (a + b)(a − b) to find 37² − 18².
  25. 25.Find the value of x² − y² when x = 5 and y = 1.
  26. 26.Use (a − b)² = a² − 2ab + b² to find 59².
  27. 27.Use (a + b)² = a² + 2ab + b² to find 24².
  28. 28.Find the value of x² − y² when x = 4 and y = 2.
  29. 29.Use (a + b)² = a² + 2ab + b² to find 14².
  30. 30.Use (a + b)² = a² + 2ab + b² to find 81².
  31. 31.Use (a + b)(a − b) = a² − b² to find 98 × 82.
  32. 32.Use (a + b)² = a² + 2ab + b² to find 17².
  33. 33.Find the value of x² + 2xy + y² when x = 11 and y = 9.
  34. 34.Use (a − b)² = a² − 2ab + b² to find 93².
  35. 35.If a + b = 19 and ab = 84, what is a² + b²?
  36. 36.Use (a − b)² = a² − 2ab + b² to find 74².
  37. 37.Use (a + b)(a − b) = a² − b² to find 64 × 56.
  38. 38.Use (a − b)² = a² − 2ab + b² to find 66².
  39. 39.Use (a + b)² = a² + 2ab + b² to find 25².
  40. 40.Use a² − b² = (a + b)(a − b) to find 74² − 2².

Answer key

  1. 10816
  2. 4761
  3. 3536
  4. 3648
  5. 4503
  6. 7744
  7. 244
  8. 3596
  9. 884
  10. 34
  11. 3564
  12. 16
  13. 11449
  14. 85
  15. 2728
  16. 8064
  17. 37
  18. 875
  19. 8360
  20. 16
  21. 8836
  22. 1
  23. 6084
  24. 1045
  25. 24
  26. 3481
  27. 576
  28. 12
  29. 196
  30. 6561
  31. 8036
  32. 289
  33. 400
  34. 8649
  35. 193
  36. 5476
  37. 3584
  38. 4356
  39. 625
  40. 5472

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