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Class 8 Maths Worksheet: Algebraic Identities

Maths worksheets lesson 61: Algebraic identities · Set 265 · 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.Use (a + b)(a − b) = a² − b² to find 73 × 67.
  2. 2.Use (a + b)(a − b) = a² − b² to find 93 × 87.
  3. 3.If a + b = 4 and ab = 3, what is a² + b²?
  4. 4.Use (a − b)² = a² − 2ab + b² to find 37².
  5. 5.If a + b = 8 and ab = 7, what is a² + b²?
  6. 6.Use (a − b)² = a² − 2ab + b² to find 78².
  7. 7.Use (a + b)² = a² + 2ab + b² to find 75².
  8. 8.Use (a + b)² = a² + 2ab + b² to find 38².
  9. 9.Use (a − b)² = a² − 2ab + b² to find 48².
  10. 10.Use (a − b)² = a² − 2ab + b² to find 75².
  11. 11.Use a² − b² = (a + b)(a − b) to find 82² − 17².
  12. 12.Find the value of x² − 2xy + y² when x = 4 and y = 2.
  13. 13.Use a² − b² = (a + b)(a − b) to find 86² − 44².
  14. 14.Use (a − b)² = a² − 2ab + b² to find 52².
  15. 15.If a − b = 10 and ab = 24, what is a² + b²?
  16. 16.Find the value of x² + 2xy + y² when x = 8 and y = 3.
  17. 17.Use (a − b)² = a² − 2ab + b² to find 49².
  18. 18.Use (a − b)² = a² − 2ab + b² to find 41².
  19. 19.Find the value of x² − 2xy + y² when x = 4 and y = 3.
  20. 20.Use (a + b)² = a² + 2ab + b² to find 13².
  21. 21.Use (a + b)² = a² + 2ab + b² to find 71².
  22. 22.If a + b = 7 and ab = 6, what is a² + b²?
  23. 23.Find the value of x² − 2xy + y² when x = 6 and y = 2.
  24. 24.If a − b = 8 and ab = 9, what is a² + b²?
  25. 25.Use a² − b² = (a + b)(a − b) to find 71² − 42².
  26. 26.Use (a − b)² = a² − 2ab + b² to find 35².
  27. 27.Use (a + b)² = a² + 2ab + b² to find 32².
  28. 28.Find the value of x² + 2xy + y² when x = 15 and y = 4.
  29. 29.Use (a + b)² = a² + 2ab + b² to find 12².
  30. 30.Use (a − b)² = a² − 2ab + b² to find 82².
  31. 31.Use (a − b)² = a² − 2ab + b² to find 77².
  32. 32.Use (a + b)(a − b) = a² − b² to find 96 × 84.
  33. 33.Use (a + b)² = a² + 2ab + b² to find 76².
  34. 34.Use (a − b)² = a² − 2ab + b² to find 58².
  35. 35.If a + b = 5 and ab = 6, what is a² + b²?
  36. 36.Use (a + b)² = a² + 2ab + b² to find 107².
  37. 37.Use (a + b)(a − b) = a² − b² to find 77 × 63.
  38. 38.Use a² − b² = (a + b)(a − b) to find 44² − 28².
  39. 39.Use (a − b)² = a² − 2ab + b² to find 43².
  40. 40.Use (a − b)² = a² − 2ab + b² to find 14².

Answer key

  1. 4891
  2. 8091
  3. 10
  4. 1369
  5. 50
  6. 6084
  7. 5625
  8. 1444
  9. 2304
  10. 5625
  11. 6435
  12. 4
  13. 5460
  14. 2704
  15. 148
  16. 121
  17. 2401
  18. 1681
  19. 1
  20. 169
  21. 5041
  22. 37
  23. 16
  24. 82
  25. 3277
  26. 1225
  27. 1024
  28. 361
  29. 144
  30. 6724
  31. 5929
  32. 8064
  33. 5776
  34. 3364
  35. 13
  36. 11449
  37. 4851
  38. 1152
  39. 1849
  40. 196

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