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Class 8 Maths Worksheet: Algebraic Identities

Maths worksheets lesson 61: Algebraic identities · Set 737 · 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 68².
  2. 2.Use a² − b² = (a + b)(a − b) to find 89² − 38².
  3. 3.Use a² − b² = (a + b)(a − b) to find 84² − 80².
  4. 4.Use (a + b)² = a² + 2ab + b² to find 77².
  5. 5.Find the value of x² − 2xy + y² when x = 15 and y = 12.
  6. 6.Use (a − b)² = a² − 2ab + b² to find 61².
  7. 7.Find the value of x² + 2xy + y² when x = 7 and y = 2.
  8. 8.Use a² − b² = (a + b)(a − b) to find 93² − 39².
  9. 9.Use a² − b² = (a + b)(a − b) to find 41² − 15².
  10. 10.If a + b = 5 and ab = 4, what is a² + b²?
  11. 11.Use (a + b)(a − b) = a² − b² to find 32 × 28.
  12. 12.Find the value of x² − 2xy + y² when x = 12 and y = 7.
  13. 13.Use (a + b)(a − b) = a² − b² to find 24 × 16.
  14. 14.Use (a + b)(a − b) = a² − b² to find 53 × 47.
  15. 15.Find the value of x² − y² when x = 6 and y = 4.
  16. 16.Use (a + b)² = a² + 2ab + b² to find 16².
  17. 17.If a + b = 10 and ab = 21, what is a² + b²?
  18. 18.Use (a − b)² = a² − 2ab + b² to find 53².
  19. 19.If a + b = 3 and ab = 2, what is a² + b²?
  20. 20.If a + b = 16 and ab = 48, what is a² + b²?
  21. 21.If a + b = 13 and ab = 42, what is a² + b²?
  22. 22.Use (a − b)² = a² − 2ab + b² to find 74².
  23. 23.Use (a + b)(a − b) = a² − b² to find 46 × 34.
  24. 24.Find the value of x² − 2xy + y² when x = 5 and y = 1.
  25. 25.If a + b = 4 and ab = 3, what is a² + b²?
  26. 26.Use (a + b)(a − b) = a² − b² to find 62 × 58.
  27. 27.Use a² − b² = (a + b)(a − b) to find 42² − 40².
  28. 28.Use (a + b)(a − b) = a² − b² to find 77 × 63.
  29. 29.Use (a + b)² = a² + 2ab + b² to find 67².
  30. 30.Use a² − b² = (a + b)(a − b) to find 21² − 12².
  31. 31.Use (a − b)² = a² − 2ab + b² to find 87².
  32. 32.Find the value of x² + 2xy + y² when x = 13 and y = 3.
  33. 33.Use a² − b² = (a + b)(a − b) to find 27² − 5².
  34. 34.Use a² − b² = (a + b)(a − b) to find 99² − 67².
  35. 35.Use a² − b² = (a + b)(a − b) to find 53² − 26².
  36. 36.Find the value of x² + 2xy + y² when x = 7 and y = 3.
  37. 37.Use a² − b² = (a + b)(a − b) to find 22² − 4².
  38. 38.Use (a − b)² = a² − 2ab + b² to find 49².
  39. 39.Use (a + b)² = a² + 2ab + b² to find 63².
  40. 40.Use (a + b)² = a² + 2ab + b² to find 104².

Answer key

  1. 4624
  2. 6477
  3. 656
  4. 5929
  5. 9
  6. 3721
  7. 81
  8. 7128
  9. 1456
  10. 17
  11. 896
  12. 25
  13. 384
  14. 2491
  15. 20
  16. 256
  17. 58
  18. 2809
  19. 5
  20. 160
  21. 85
  22. 5476
  23. 1564
  24. 16
  25. 10
  26. 3596
  27. 164
  28. 4851
  29. 4489
  30. 297
  31. 7569
  32. 256
  33. 704
  34. 5312
  35. 2133
  36. 100
  37. 468
  38. 2401
  39. 3969
  40. 10816

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