← Algebraic identities lesson New set →

Class 8 Maths Worksheet: Algebraic Identities

Maths worksheets lesson 61: Algebraic identities · Set 105 · 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.Find the value of x² − y² when x = 8 and y = 6.
  2. 2.If a + b = 4 and ab = 3, what is a² + b²?
  3. 3.Use a² − b² = (a + b)(a − b) to find 81² − 71².
  4. 4.Use (a + b)(a − b) = a² − b² to find 67 × 53.
  5. 5.Use a² − b² = (a + b)(a − b) to find 76² − 28².
  6. 6.Use (a − b)² = a² − 2ab + b² to find 41².
  7. 7.Use (a − b)² = a² − 2ab + b² to find 69².
  8. 8.Use a² − b² = (a + b)(a − b) to find 37² − 1².
  9. 9.Find the value of x² − y² when x = 4 and y = 3.
  10. 10.Use (a − b)² = a² − 2ab + b² to find 55².
  11. 11.Find the value of x² − y² when x = 14 and y = 3.
  12. 12.Use (a − b)² = a² − 2ab + b² to find 97².
  13. 13.Use (a + b)² = a² + 2ab + b² to find 42².
  14. 14.Find the value of x² − y² when x = 12 and y = 1.
  15. 15.Find the value of x² − 2xy + y² when x = 4 and y = 2.
  16. 16.Use a² − b² = (a + b)(a − b) to find 62² − 61².
  17. 17.Use (a + b)² = a² + 2ab + b² to find 89².
  18. 18.Find the value of x² − 2xy + y² when x = 4 and y = 3.
  19. 19.Use (a − b)² = a² − 2ab + b² to find 16².
  20. 20.Use (a − b)² = a² − 2ab + b² to find 19².
  21. 21.Use (a + b)(a − b) = a² − b² to find 51 × 49.
  22. 22.Use (a + b)(a − b) = a² − b² to find 35 × 25.
  23. 23.Use (a − b)² = a² − 2ab + b² to find 26².
  24. 24.Use (a + b)(a − b) = a² − b² to find 104 × 96.
  25. 25.Use a² − b² = (a + b)(a − b) to find 73² − 51².
  26. 26.If a − b = 8 and ab = 33, what is a² + b²?
  27. 27.Use (a + b)² = a² + 2ab + b² to find 64².
  28. 28.Use (a + b)² = a² + 2ab + b² to find 36².
  29. 29.Use a² − b² = (a + b)(a − b) to find 82² − 50².
  30. 30.Use (a + b)² = a² + 2ab + b² to find 37².
  31. 31.Use (a + b)(a − b) = a² − b² to find 103 × 97.
  32. 32.Find the value of x² − y² when x = 10 and y = 3.
  33. 33.Use (a + b)² = a² + 2ab + b² to find 86².
  34. 34.Find the value of x² + 2xy + y² when x = 12 and y = 5.
  35. 35.Use a² − b² = (a + b)(a − b) to find 74² − 71².
  36. 36.Use a² − b² = (a + b)(a − b) to find 20² − 15².
  37. 37.Use (a − b)² = a² − 2ab + b² to find 45².
  38. 38.Use (a + b)² = a² + 2ab + b² to find 97².
  39. 39.If a − b = 6 and ab = 16, what is a² + b²?
  40. 40.Use (a + b)(a − b) = a² − b² to find 42 × 38.

Answer key

  1. 28
  2. 10
  3. 1520
  4. 3551
  5. 4992
  6. 1681
  7. 4761
  8. 1368
  9. 7
  10. 3025
  11. 187
  12. 9409
  13. 1764
  14. 143
  15. 4
  16. 123
  17. 7921
  18. 1
  19. 256
  20. 361
  21. 2499
  22. 875
  23. 676
  24. 9984
  25. 2728
  26. 130
  27. 4096
  28. 1296
  29. 4224
  30. 1369
  31. 9991
  32. 91
  33. 7396
  34. 289
  35. 435
  36. 175
  37. 2025
  38. 9409
  39. 68
  40. 1596

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