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Class 8 Maths Worksheet: Algebraic Identities

Maths worksheets lesson 61: Algebraic identities · Set 984 · 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 = 10 and y = 4.
  2. 2.Use (a − b)² = a² − 2ab + b² to find 32².
  3. 3.If a − b = 3 and ab = 4, what is a² + b²?
  4. 4.Use a² − b² = (a + b)(a − b) to find 58² − 3².
  5. 5.Find the value of x² − y² when x = 14 and y = 2.
  6. 6.Find the value of x² − 2xy + y² when x = 4 and y = 1.
  7. 7.Use (a + b)² = a² + 2ab + b² to find 107².
  8. 8.Use (a + b)² = a² + 2ab + b² to find 85².
  9. 9.Find the value of x² − y² when x = 7 and y = 6.
  10. 10.Use (a − b)² = a² − 2ab + b² to find 63².
  11. 11.Use a² − b² = (a + b)(a − b) to find 43² − 39².
  12. 12.Use (a + b)² = a² + 2ab + b² to find 96².
  13. 13.Use (a + b)(a − b) = a² − b² to find 27 × 13.
  14. 14.Find the value of x² − y² when x = 9 and y = 8.
  15. 15.Use (a + b)² = a² + 2ab + b² to find 17².
  16. 16.Use a² − b² = (a + b)(a − b) to find 69² − 17².
  17. 17.Find the value of x² − 2xy + y² when x = 14 and y = 7.
  18. 18.Use a² − b² = (a + b)(a − b) to find 82² − 45².
  19. 19.Use (a + b)² = a² + 2ab + b² to find 97².
  20. 20.Use (a + b)² = a² + 2ab + b² to find 56².
  21. 21.Find the value of x² + 2xy + y² when x = 13 and y = 7.
  22. 22.Use (a + b)² = a² + 2ab + b² to find 58².
  23. 23.Find the value of x² − y² when x = 12 and y = 7.
  24. 24.Use a² − b² = (a + b)(a − b) to find 78² − 40².
  25. 25.If a + b = 12 and ab = 20, what is a² + b²?
  26. 26.Use (a + b)² = a² + 2ab + b² to find 103².
  27. 27.If a + b = 13 and ab = 22, what is a² + b²?
  28. 28.Use (a + b)² = a² + 2ab + b² to find 41².
  29. 29.Use (a + b)(a − b) = a² − b² to find 36 × 24.
  30. 30.Find the value of x² − 2xy + y² when x = 12 and y = 3.
  31. 31.If a + b = 18 and ab = 77, what is a² + b²?
  32. 32.If a + b = 11 and ab = 24, what is a² + b²?
  33. 33.Use (a + b)² = a² + 2ab + b² to find 91².
  34. 34.If a + b = 5 and ab = 6, what is a² + b²?
  35. 35.Use (a + b)(a − b) = a² − b² to find 97 × 83.
  36. 36.Use (a + b)(a − b) = a² − b² to find 69 × 51.
  37. 37.Use (a − b)² = a² − 2ab + b² to find 14².
  38. 38.Use a² − b² = (a + b)(a − b) to find 40² − 5².
  39. 39.Use (a − b)² = a² − 2ab + b² to find 67².
  40. 40.Use (a + b)(a − b) = a² − b² to find 81 × 79.

Answer key

  1. 196
  2. 1024
  3. 17
  4. 3355
  5. 192
  6. 9
  7. 11449
  8. 7225
  9. 13
  10. 3969
  11. 328
  12. 9216
  13. 351
  14. 17
  15. 289
  16. 4472
  17. 49
  18. 4699
  19. 9409
  20. 3136
  21. 400
  22. 3364
  23. 95
  24. 4484
  25. 104
  26. 10609
  27. 125
  28. 1681
  29. 864
  30. 81
  31. 170
  32. 73
  33. 8281
  34. 13
  35. 8051
  36. 3519
  37. 196
  38. 1575
  39. 4489
  40. 6399

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