← Algebraic identities lesson New set →

Class 8 Maths Worksheet: Algebraic Identities

Maths worksheets lesson 61: Algebraic identities · Set 855 · 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)² = a² − 2ab + b² to find 19².
  2. 2.Use (a − b)² = a² − 2ab + b² to find 64².
  3. 3.Use (a + b)² = a² + 2ab + b² to find 61².
  4. 4.Use (a + b)(a − b) = a² − b² to find 84 × 76.
  5. 5.Use (a + b)² = a² + 2ab + b² to find 82².
  6. 6.Use (a − b)² = a² − 2ab + b² to find 96².
  7. 7.Use a² − b² = (a + b)(a − b) to find 82² − 77².
  8. 8.Use (a − b)² = a² − 2ab + b² to find 71².
  9. 9.Use (a − b)² = a² − 2ab + b² to find 48².
  10. 10.Find the value of x² − y² when x = 4 and y = 3.
  11. 11.Use (a − b)² = a² − 2ab + b² to find 87².
  12. 12.Use (a + b)(a − b) = a² − b² to find 65 × 55.
  13. 13.Use a² − b² = (a + b)(a − b) to find 28² − 26².
  14. 14.Use a² − b² = (a + b)(a − b) to find 32² − 24².
  15. 15.Use (a − b)² = a² − 2ab + b² to find 93².
  16. 16.Use (a + b)² = a² + 2ab + b² to find 16².
  17. 17.Use a² − b² = (a + b)(a − b) to find 78² − 35².
  18. 18.If a − b = 6 and ab = 7, what is a² + b²?
  19. 19.If a − b = 4 and ab = 45, what is a² + b²?
  20. 20.Use (a − b)² = a² − 2ab + b² to find 53².
  21. 21.Find the value of x² − y² when x = 11 and y = 2.
  22. 22.If a + b = 15 and ab = 36, what is a² + b²?
  23. 23.Use (a − b)² = a² − 2ab + b² to find 27².
  24. 24.Use (a + b)(a − b) = a² − b² to find 47 × 33.
  25. 25.Use (a − b)² = a² − 2ab + b² to find 12².
  26. 26.Use (a − b)² = a² − 2ab + b² to find 91².
  27. 27.Use (a + b)² = a² + 2ab + b² to find 25².
  28. 28.Use (a + b)² = a² + 2ab + b² to find 81².
  29. 29.Use (a + b)² = a² + 2ab + b² to find 17².
  30. 30.Use (a + b)² = a² + 2ab + b² to find 14².
  31. 31.If a + b = 3 and ab = 2, what is a² + b²?
  32. 32.Use a² − b² = (a + b)(a − b) to find 24² − 2².
  33. 33.Use (a + b)² = a² + 2ab + b² to find 23².
  34. 34.Use (a − b)² = a² − 2ab + b² to find 39².
  35. 35.If a + b = 17 and ab = 72, what is a² + b²?
  36. 36.Use (a − b)² = a² − 2ab + b² to find 16².
  37. 37.Find the value of x² − y² when x = 5 and y = 1.
  38. 38.Find the value of x² + 2xy + y² when x = 11 and y = 1.
  39. 39.If a − b = 3 and ab = 4, what is a² + b²?
  40. 40.Use (a − b)² = a² − 2ab + b² to find 67².

Answer key

  1. 361
  2. 4096
  3. 3721
  4. 6384
  5. 6724
  6. 9216
  7. 795
  8. 5041
  9. 2304
  10. 7
  11. 7569
  12. 3575
  13. 108
  14. 448
  15. 8649
  16. 256
  17. 4859
  18. 50
  19. 106
  20. 2809
  21. 117
  22. 153
  23. 729
  24. 1551
  25. 144
  26. 8281
  27. 625
  28. 6561
  29. 289
  30. 196
  31. 5
  32. 572
  33. 529
  34. 1521
  35. 145
  36. 256
  37. 24
  38. 144
  39. 17
  40. 4489

Free maths worksheets lessons, practice and worksheets at talentjr.in/maths-worksheets