← Algebraic identities lesson New set →

Class 8 Maths Worksheet: Algebraic Identities

Maths worksheets lesson 61: Algebraic identities · Set 417 · 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 41².
  2. 2.If a − b = 7 and ab = 60, what is a² + b²?
  3. 3.Use (a + b)(a − b) = a² − b² to find 91 × 89.
  4. 4.Find the value of x² + 2xy + y² when x = 5 and y = 2.
  5. 5.Use (a + b)(a − b) = a² − b² to find 89 × 71.
  6. 6.If a − b = 10 and ab = 24, what is a² + b²?
  7. 7.Find the value of x² − y² when x = 11 and y = 9.
  8. 8.Find the value of x² − y² when x = 5 and y = 1.
  9. 9.Use (a − b)² = a² − 2ab + b² to find 42².
  10. 10.Use (a + b)(a − b) = a² − b² to find 35 × 25.
  11. 11.Use (a − b)² = a² − 2ab + b² to find 18².
  12. 12.Use (a − b)² = a² − 2ab + b² to find 22².
  13. 13.Use a² − b² = (a + b)(a − b) to find 80² − 43².
  14. 14.Use (a + b)² = a² + 2ab + b² to find 28².
  15. 15.Use (a − b)² = a² − 2ab + b² to find 11².
  16. 16.Find the value of x² − y² when x = 6 and y = 5.
  17. 17.Use a² − b² = (a + b)(a − b) to find 64² − 27².
  18. 18.Use (a + b)² = a² + 2ab + b² to find 96².
  19. 19.Use (a + b)² = a² + 2ab + b² to find 34².
  20. 20.Use (a + b)² = a² + 2ab + b² to find 85².
  21. 21.If a + b = 5 and ab = 6, what is a² + b²?
  22. 22.Use (a + b)(a − b) = a² − b² to find 54 × 46.
  23. 23.Use (a − b)² = a² − 2ab + b² to find 25².
  24. 24.Find the value of x² − 2xy + y² when x = 11 and y = 10.
  25. 25.Use (a − b)² = a² − 2ab + b² to find 75².
  26. 26.Use (a + b)² = a² + 2ab + b² to find 22².
  27. 27.Use (a + b)² = a² + 2ab + b² to find 38².
  28. 28.Use (a + b)² = a² + 2ab + b² to find 14².
  29. 29.If a − b = 2 and ab = 24, what is a² + b²?
  30. 30.If a + b = 14 and ab = 33, what is a² + b²?
  31. 31.Find the value of x² + 2xy + y² when x = 6 and y = 2.
  32. 32.If a + b = 21 and ab = 108, what is a² + b²?
  33. 33.Use a² − b² = (a + b)(a − b) to find 83² − 26².
  34. 34.Use a² − b² = (a + b)(a − b) to find 27² − 9².
  35. 35.Use (a + b)² = a² + 2ab + b² to find 82².
  36. 36.Use a² − b² = (a + b)(a − b) to find 90² − 34².
  37. 37.Use (a + b)(a − b) = a² − b² to find 81 × 79.
  38. 38.Use (a + b)(a − b) = a² − b² to find 44 × 36.
  39. 39.Use a² − b² = (a + b)(a − b) to find 65² − 15².
  40. 40.Use a² − b² = (a + b)(a − b) to find 64² − 53².

Answer key

  1. 1681
  2. 169
  3. 8099
  4. 49
  5. 6319
  6. 148
  7. 40
  8. 24
  9. 1764
  10. 875
  11. 324
  12. 484
  13. 4551
  14. 784
  15. 121
  16. 11
  17. 3367
  18. 9216
  19. 1156
  20. 7225
  21. 13
  22. 2484
  23. 625
  24. 1
  25. 5625
  26. 484
  27. 1444
  28. 196
  29. 52
  30. 130
  31. 64
  32. 225
  33. 6213
  34. 648
  35. 6724
  36. 6944
  37. 6399
  38. 1584
  39. 4000
  40. 1287

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