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Class 8 Maths Worksheet: Algebraic Identities

Maths worksheets lesson 61: Algebraic identities · Set 543 · 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 85².
  2. 2.If a − b = 2 and ab = 3, what is a² + b²?
  3. 3.Use (a − b)² = a² − 2ab + b² to find 58².
  4. 4.Use a² − b² = (a + b)(a − b) to find 88² − 74².
  5. 5.Use (a − b)² = a² − 2ab + b² to find 16².
  6. 6.If a − b = 3 and ab = 108, what is a² + b²?
  7. 7.Find the value of x² + 2xy + y² when x = 9 and y = 2.
  8. 8.Find the value of x² + 2xy + y² when x = 5 and y = 1.
  9. 9.Use a² − b² = (a + b)(a − b) to find 89² − 16².
  10. 10.Find the value of x² − 2xy + y² when x = 14 and y = 6.
  11. 11.Use (a + b)² = a² + 2ab + b² to find 61².
  12. 12.Use a² − b² = (a + b)(a − b) to find 58² − 47².
  13. 13.If a + b = 20 and ab = 96, what is a² + b²?
  14. 14.Use (a + b)² = a² + 2ab + b² to find 71².
  15. 15.Use a² − b² = (a + b)(a − b) to find 72² − 6².
  16. 16.Use (a + b)² = a² + 2ab + b² to find 52².
  17. 17.Use (a − b)² = a² − 2ab + b² to find 37².
  18. 18.Use (a + b)² = a² + 2ab + b² to find 58².
  19. 19.Use (a + b)² = a² + 2ab + b² to find 73².
  20. 20.Use (a − b)² = a² − 2ab + b² to find 71².
  21. 21.Use (a − b)² = a² − 2ab + b² to find 88².
  22. 22.If a + b = 9 and ab = 18, what is a² + b²?
  23. 23.Use a² − b² = (a + b)(a − b) to find 63² − 49².
  24. 24.Find the value of x² − 2xy + y² when x = 6 and y = 2.
  25. 25.Use (a − b)² = a² − 2ab + b² to find 39².
  26. 26.Use a² − b² = (a + b)(a − b) to find 96² − 62².
  27. 27.Use a² − b² = (a + b)(a − b) to find 61² − 23².
  28. 28.Use (a + b)² = a² + 2ab + b² to find 14².
  29. 29.Use (a + b)² = a² + 2ab + b² to find 13².
  30. 30.Use (a + b)² = a² + 2ab + b² to find 94².
  31. 31.Use (a + b)² = a² + 2ab + b² to find 95².
  32. 32.Find the value of x² − 2xy + y² when x = 7 and y = 4.
  33. 33.If a + b = 21 and ab = 110, what is a² + b²?
  34. 34.Use (a + b)(a − b) = a² − b² to find 28 × 12.
  35. 35.Use (a − b)² = a² − 2ab + b² to find 65².
  36. 36.Use (a − b)² = a² − 2ab + b² to find 62².
  37. 37.Use (a − b)² = a² − 2ab + b² to find 19².
  38. 38.Use a² − b² = (a + b)(a − b) to find 29² − 4².
  39. 39.Use a² − b² = (a + b)(a − b) to find 29² − 5².
  40. 40.Use a² − b² = (a + b)(a − b) to find 68² − 49².

Answer key

  1. 7225
  2. 10
  3. 3364
  4. 2268
  5. 256
  6. 225
  7. 121
  8. 36
  9. 7665
  10. 64
  11. 3721
  12. 1155
  13. 208
  14. 5041
  15. 5148
  16. 2704
  17. 1369
  18. 3364
  19. 5329
  20. 5041
  21. 7744
  22. 45
  23. 1568
  24. 16
  25. 1521
  26. 5372
  27. 3192
  28. 196
  29. 169
  30. 8836
  31. 9025
  32. 9
  33. 221
  34. 336
  35. 4225
  36. 3844
  37. 361
  38. 825
  39. 816
  40. 2223

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