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Class 8 Maths Worksheet: Algebraic Identities

Maths worksheets lesson 61: Algebraic identities · Set 695 · 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.Find the value of x² + 2xy + y² when x = 8 and y = 7.
  2. 2.Use (a − b)² = a² − 2ab + b² to find 24².
  3. 3.Use (a − b)² = a² − 2ab + b² to find 61².
  4. 4.Use (a + b)(a − b) = a² − b² to find 22 × 18.
  5. 5.Find the value of x² + 2xy + y² when x = 13 and y = 7.
  6. 6.Use a² − b² = (a + b)(a − b) to find 29² − 3².
  7. 7.Use (a + b)(a − b) = a² − b² to find 39 × 21.
  8. 8.Use (a + b)² = a² + 2ab + b² to find 74².
  9. 9.Use a² − b² = (a + b)(a − b) to find 95² − 8².
  10. 10.Use a² − b² = (a + b)(a − b) to find 63² − 15².
  11. 11.Use a² − b² = (a + b)(a − b) to find 45² − 37².
  12. 12.Use (a + b)² = a² + 2ab + b² to find 94².
  13. 13.If a + b = 12 and ab = 27, what is a² + b²?
  14. 14.Find the value of x² + 2xy + y² when x = 13 and y = 9.
  15. 15.Use a² − b² = (a + b)(a − b) to find 64² − 27².
  16. 16.Use (a + b)² = a² + 2ab + b² to find 33².
  17. 17.Use a² − b² = (a + b)(a − b) to find 58² − 11².
  18. 18.If a + b = 10 and ab = 9, what is a² + b²?
  19. 19.Find the value of x² − 2xy + y² when x = 12 and y = 4.
  20. 20.If a + b = 11 and ab = 28, what is a² + b²?
  21. 21.Find the value of x² − 2xy + y² when x = 4 and y = 1.
  22. 22.Use (a − b)² = a² − 2ab + b² to find 28².
  23. 23.If a − b = 5 and ab = 24, what is a² + b²?
  24. 24.Find the value of x² − 2xy + y² when x = 5 and y = 2.
  25. 25.Find the value of x² − 2xy + y² when x = 11 and y = 3.
  26. 26.Use a² − b² = (a + b)(a − b) to find 72² − 70².
  27. 27.If a + b = 18 and ab = 77, what is a² + b²?
  28. 28.Find the value of x² − y² when x = 6 and y = 5.
  29. 29.Use (a − b)² = a² − 2ab + b² to find 67².
  30. 30.Use (a + b)² = a² + 2ab + b² to find 29².
  31. 31.If a − b = 6 and ab = 40, what is a² + b²?
  32. 32.Find the value of x² − y² when x = 5 and y = 2.
  33. 33.Use a² − b² = (a + b)(a − b) to find 31² − 26².
  34. 34.Use (a + b)² = a² + 2ab + b² to find 51².
  35. 35.If a − b = 3 and ab = 4, what is a² + b²?
  36. 36.Use (a + b)(a − b) = a² − b² to find 72 × 68.
  37. 37.Use (a + b)(a − b) = a² − b² to find 24 × 16.
  38. 38.Find the value of x² + 2xy + y² when x = 12 and y = 1.
  39. 39.Use (a + b)² = a² + 2ab + b² to find 25².
  40. 40.If a + b = 8 and ab = 15, what is a² + b²?

Answer key

  1. 225
  2. 576
  3. 3721
  4. 396
  5. 400
  6. 832
  7. 819
  8. 5476
  9. 8961
  10. 3744
  11. 656
  12. 8836
  13. 90
  14. 484
  15. 3367
  16. 1089
  17. 3243
  18. 82
  19. 64
  20. 65
  21. 9
  22. 784
  23. 73
  24. 9
  25. 64
  26. 284
  27. 170
  28. 11
  29. 4489
  30. 841
  31. 116
  32. 21
  33. 285
  34. 2601
  35. 17
  36. 4896
  37. 384
  38. 169
  39. 625
  40. 34

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