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Class 8 Maths Worksheet: Algebraic Identities

Maths worksheets lesson 61: Algebraic identities · Set 923 · 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 a² − b² = (a + b)(a − b) to find 50² − 24².
  2. 2.Use (a − b)² = a² − 2ab + b² to find 59².
  3. 3.Use a² − b² = (a + b)(a − b) to find 59² − 36².
  4. 4.If a − b = 2 and ab = 48, what is a² + b²?
  5. 5.Use (a − b)² = a² − 2ab + b² to find 13².
  6. 6.Use (a + b)(a − b) = a² − b² to find 99 × 81.
  7. 7.Find the value of x² − y² when x = 4 and y = 2.
  8. 8.Use a² − b² = (a + b)(a − b) to find 60² − 10².
  9. 9.If a − b = 8 and ab = 9, what is a² + b²?
  10. 10.Use (a + b)² = a² + 2ab + b² to find 17².
  11. 11.Use (a − b)² = a² − 2ab + b² to find 54².
  12. 12.Find the value of x² − 2xy + y² when x = 14 and y = 1.
  13. 13.Use (a + b)² = a² + 2ab + b² to find 14².
  14. 14.Use (a − b)² = a² − 2ab + b² to find 49².
  15. 15.Use a² − b² = (a + b)(a − b) to find 22² − 18².
  16. 16.Find the value of x² + 2xy + y² when x = 7 and y = 2.
  17. 17.If a + b = 13 and ab = 12, what is a² + b²?
  18. 18.Use (a − b)² = a² − 2ab + b² to find 87².
  19. 19.Use (a + b)(a − b) = a² − b² to find 81 × 79.
  20. 20.If a + b = 3 and ab = 2, what is a² + b²?
  21. 21.Use (a + b)² = a² + 2ab + b² to find 49².
  22. 22.Use (a − b)² = a² − 2ab + b² to find 97².
  23. 23.Use (a + b)² = a² + 2ab + b² to find 86².
  24. 24.Find the value of x² + 2xy + y² when x = 4 and y = 2.
  25. 25.If a + b = 4 and ab = 3, what is a² + b²?
  26. 26.Use a² − b² = (a + b)(a − b) to find 89² − 52².
  27. 27.If a + b = 15 and ab = 54, what is a² + b²?
  28. 28.Use (a + b)² = a² + 2ab + b² to find 48².
  29. 29.Use (a − b)² = a² − 2ab + b² to find 46².
  30. 30.If a − b = 7 and ab = 8, what is a² + b²?
  31. 31.Find the value of x² − 2xy + y² when x = 14 and y = 13.
  32. 32.Find the value of x² − 2xy + y² when x = 7 and y = 2.
  33. 33.Find the value of x² − 2xy + y² when x = 9 and y = 3.
  34. 34.Use (a + b)(a − b) = a² − b² to find 44 × 36.
  35. 35.Use (a + b)² = a² + 2ab + b² to find 102².
  36. 36.Use (a − b)² = a² − 2ab + b² to find 85².
  37. 37.Use (a + b)² = a² + 2ab + b² to find 39².
  38. 38.Use a² − b² = (a + b)(a − b) to find 88² − 81².
  39. 39.Use (a + b)² = a² + 2ab + b² to find 101².
  40. 40.Use (a − b)² = a² − 2ab + b² to find 96².

Answer key

  1. 1924
  2. 3481
  3. 2185
  4. 100
  5. 169
  6. 8019
  7. 12
  8. 3500
  9. 82
  10. 289
  11. 2916
  12. 169
  13. 196
  14. 2401
  15. 160
  16. 81
  17. 145
  18. 7569
  19. 6399
  20. 5
  21. 2401
  22. 9409
  23. 7396
  24. 36
  25. 10
  26. 5217
  27. 117
  28. 2304
  29. 2116
  30. 65
  31. 1
  32. 25
  33. 36
  34. 1584
  35. 10404
  36. 7225
  37. 1521
  38. 1183
  39. 10201
  40. 9216

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