← Algebraic identities lesson New set →

Class 8 Maths Worksheet: Algebraic Identities

Maths worksheets lesson 61: Algebraic identities · Set 218 · 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 63².
  2. 2.Use (a + b)(a − b) = a² − b² to find 45 × 35.
  3. 3.Find the value of x² − 2xy + y² when x = 4 and y = 3.
  4. 4.Use (a + b)² = a² + 2ab + b² to find 28².
  5. 5.Use a² − b² = (a + b)(a − b) to find 20² − 6².
  6. 6.Find the value of x² − 2xy + y² when x = 10 and y = 3.
  7. 7.Find the value of x² + 2xy + y² when x = 10 and y = 3.
  8. 8.Use a² − b² = (a + b)(a − b) to find 61² − 55².
  9. 9.Use a² − b² = (a + b)(a − b) to find 20² − 15².
  10. 10.Use a² − b² = (a + b)(a − b) to find 81² − 72².
  11. 11.Use (a − b)² = a² − 2ab + b² to find 44².
  12. 12.Use (a + b)² = a² + 2ab + b² to find 106².
  13. 13.Use (a + b)² = a² + 2ab + b² to find 87².
  14. 14.Use a² − b² = (a + b)(a − b) to find 75² − 64².
  15. 15.If a + b = 7 and ab = 6, what is a² + b²?
  16. 16.If a + b = 15 and ab = 54, what is a² + b²?
  17. 17.Use (a + b)² = a² + 2ab + b² to find 26².
  18. 18.Use (a + b)² = a² + 2ab + b² to find 65².
  19. 19.Use (a + b)(a − b) = a² − b² to find 33 × 27.
  20. 20.Use (a − b)² = a² − 2ab + b² to find 45².
  21. 21.Find the value of x² − 2xy + y² when x = 14 and y = 9.
  22. 22.Use (a − b)² = a² − 2ab + b² to find 96².
  23. 23.Use (a − b)² = a² − 2ab + b² to find 97².
  24. 24.If a + b = 3 and ab = 2, what is a² + b²?
  25. 25.Use (a + b)(a − b) = a² − b² to find 84 × 76.
  26. 26.Use a² − b² = (a + b)(a − b) to find 97² − 32².
  27. 27.Use (a + b)² = a² + 2ab + b² to find 84².
  28. 28.Use (a + b)(a − b) = a² − b² to find 101 × 99.
  29. 29.Use (a − b)² = a² − 2ab + b² to find 23².
  30. 30.Use (a + b)² = a² + 2ab + b² to find 22².
  31. 31.Use (a − b)² = a² − 2ab + b² to find 72².
  32. 32.If a + b = 13 and ab = 12, what is a² + b²?
  33. 33.Find the value of x² + 2xy + y² when x = 8 and y = 2.
  34. 34.Use (a + b)(a − b) = a² − b² to find 36 × 24.
  35. 35.Use (a − b)² = a² − 2ab + b² to find 73².
  36. 36.Use a² − b² = (a + b)(a − b) to find 60² − 46².
  37. 37.Use (a + b)² = a² + 2ab + b² to find 64².
  38. 38.Use (a − b)² = a² − 2ab + b² to find 52².
  39. 39.Use (a − b)² = a² − 2ab + b² to find 35².
  40. 40.Use (a + b)(a − b) = a² − b² to find 32 × 28.

Answer key

  1. 3969
  2. 1575
  3. 1
  4. 784
  5. 364
  6. 49
  7. 169
  8. 696
  9. 175
  10. 1377
  11. 1936
  12. 11236
  13. 7569
  14. 1529
  15. 37
  16. 117
  17. 676
  18. 4225
  19. 891
  20. 2025
  21. 25
  22. 9216
  23. 9409
  24. 5
  25. 6384
  26. 8385
  27. 7056
  28. 9999
  29. 529
  30. 484
  31. 5184
  32. 145
  33. 100
  34. 864
  35. 5329
  36. 1484
  37. 4096
  38. 2704
  39. 1225
  40. 896

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