← Algebraic identities lesson New set →

Class 8 Maths Worksheet: Algebraic Identities

Maths worksheets lesson 61: Algebraic identities · Set 251 · 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 95².
  2. 2.If a − b = 3 and ab = 108, what is a² + b²?
  3. 3.Use (a + b)² = a² + 2ab + b² to find 47².
  4. 4.Use (a − b)² = a² − 2ab + b² to find 89².
  5. 5.Use (a + b)² = a² + 2ab + b² to find 83².
  6. 6.Use (a − b)² = a² − 2ab + b² to find 17².
  7. 7.Use (a − b)² = a² − 2ab + b² to find 44².
  8. 8.Use (a + b)(a − b) = a² − b² to find 22 × 18.
  9. 9.If a − b = 7 and ab = 30, what is a² + b²?
  10. 10.Use a² − b² = (a + b)(a − b) to find 66² − 40².
  11. 11.If a + b = 7 and ab = 6, what is a² + b²?
  12. 12.Use a² − b² = (a + b)(a − b) to find 24² − 18².
  13. 13.Find the value of x² − 2xy + y² when x = 10 and y = 7.
  14. 14.Use (a + b)² = a² + 2ab + b² to find 28².
  15. 15.Use (a − b)² = a² − 2ab + b² to find 93².
  16. 16.Find the value of x² − y² when x = 12 and y = 6.
  17. 17.Use (a + b)(a − b) = a² − b² to find 49 × 31.
  18. 18.Use (a + b)(a − b) = a² − b² to find 54 × 46.
  19. 19.Find the value of x² − 2xy + y² when x = 12 and y = 8.
  20. 20.Find the value of x² − y² when x = 12 and y = 11.
  21. 21.Use a² − b² = (a + b)(a − b) to find 22² − 6².
  22. 22.Find the value of x² + 2xy + y² when x = 11 and y = 7.
  23. 23.Use a² − b² = (a + b)(a − b) to find 76² − 44².
  24. 24.Find the value of x² + 2xy + y² when x = 10 and y = 9.
  25. 25.Use (a + b)(a − b) = a² − b² to find 32 × 28.
  26. 26.Use (a + b)² = a² + 2ab + b² to find 85².
  27. 27.Use a² − b² = (a + b)(a − b) to find 74² − 44².
  28. 28.Use (a + b)² = a² + 2ab + b² to find 31².
  29. 29.Find the value of x² − y² when x = 14 and y = 9.
  30. 30.If a + b = 11 and ab = 28, what is a² + b²?
  31. 31.Use (a + b)(a − b) = a² − b² to find 104 × 96.
  32. 32.If a − b = 1 and ab = 12, what is a² + b²?
  33. 33.Use (a + b)(a − b) = a² − b² to find 79 × 61.
  34. 34.Use a² − b² = (a + b)(a − b) to find 94² − 11².
  35. 35.Use (a − b)² = a² − 2ab + b² to find 98².
  36. 36.Use (a + b)(a − b) = a² − b² to find 74 × 66.
  37. 37.If a − b = 10 and ab = 11, what is a² + b²?
  38. 38.If a + b = 10 and ab = 16, what is a² + b²?
  39. 39.Use (a + b)(a − b) = a² − b² to find 84 × 76.
  40. 40.Use a² − b² = (a + b)(a − b) to find 29² − 7².

Answer key

  1. 9025
  2. 225
  3. 2209
  4. 7921
  5. 6889
  6. 289
  7. 1936
  8. 396
  9. 109
  10. 2756
  11. 37
  12. 252
  13. 9
  14. 784
  15. 8649
  16. 108
  17. 1519
  18. 2484
  19. 16
  20. 23
  21. 448
  22. 324
  23. 3840
  24. 361
  25. 896
  26. 7225
  27. 3540
  28. 961
  29. 115
  30. 65
  31. 9984
  32. 25
  33. 4819
  34. 8715
  35. 9604
  36. 4884
  37. 122
  38. 68
  39. 6384
  40. 792

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