← Algebraic identities lesson New set →

Class 8 Maths Worksheet: Algebraic Identities

Maths worksheets lesson 61: Algebraic identities · Set 420 · 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.If a − b = 1 and ab = 2, what is a² + b²?
  2. 2.Use (a − b)² = a² − 2ab + b² to find 32².
  3. 3.Find the value of x² − y² when x = 10 and y = 5.
  4. 4.If a + b = 4 and ab = 3, what is a² + b²?
  5. 5.Use (a + b)² = a² + 2ab + b² to find 41².
  6. 6.Use (a − b)² = a² − 2ab + b² to find 93².
  7. 7.Use (a + b)(a − b) = a² − b² to find 24 × 16.
  8. 8.Use (a + b)² = a² + 2ab + b² to find 11².
  9. 9.If a + b = 17 and ab = 72, what is a² + b²?
  10. 10.Find the value of x² − y² when x = 10 and y = 2.
  11. 11.Use (a + b)² = a² + 2ab + b² to find 63².
  12. 12.Find the value of x² − 2xy + y² when x = 6 and y = 5.
  13. 13.Use (a − b)² = a² − 2ab + b² to find 18².
  14. 14.If a + b = 5 and ab = 6, what is a² + b²?
  15. 15.Use a² − b² = (a + b)(a − b) to find 40² − 1².
  16. 16.Use (a + b)(a − b) = a² − b² to find 31 × 29.
  17. 17.If a − b = 3 and ab = 4, what is a² + b²?
  18. 18.Use (a + b)² = a² + 2ab + b² to find 65².
  19. 19.If a − b = 1 and ab = 6, what is a² + b²?
  20. 20.If a + b = 7 and ab = 10, what is a² + b²?
  21. 21.If a − b = 6 and ab = 16, what is a² + b²?
  22. 22.Find the value of x² − y² when x = 10 and y = 9.
  23. 23.If a + b = 11 and ab = 18, what is a² + b²?
  24. 24.Use (a + b)² = a² + 2ab + b² to find 21².
  25. 25.Use (a − b)² = a² − 2ab + b² to find 29².
  26. 26.Find the value of x² − 2xy + y² when x = 6 and y = 3.
  27. 27.Use (a − b)² = a² − 2ab + b² to find 12².
  28. 28.Use a² − b² = (a + b)(a − b) to find 49² − 40².
  29. 29.Use (a + b)² = a² + 2ab + b² to find 71².
  30. 30.Use (a − b)² = a² − 2ab + b² to find 24².
  31. 31.Use (a + b)² = a² + 2ab + b² to find 53².
  32. 32.Use (a − b)² = a² − 2ab + b² to find 74².
  33. 33.Find the value of x² − y² when x = 15 and y = 10.
  34. 34.Use a² − b² = (a + b)(a − b) to find 73² − 27².
  35. 35.Use (a + b)² = a² + 2ab + b² to find 34².
  36. 36.Use (a − b)² = a² − 2ab + b² to find 66².
  37. 37.Find the value of x² + 2xy + y² when x = 14 and y = 10.
  38. 38.If a + b = 9 and ab = 14, what is a² + b²?
  39. 39.Find the value of x² − y² when x = 4 and y = 2.
  40. 40.If a + b = 3 and ab = 2, what is a² + b²?

Answer key

  1. 5
  2. 1024
  3. 75
  4. 10
  5. 1681
  6. 8649
  7. 384
  8. 121
  9. 145
  10. 96
  11. 3969
  12. 1
  13. 324
  14. 13
  15. 1599
  16. 899
  17. 17
  18. 4225
  19. 13
  20. 29
  21. 68
  22. 19
  23. 85
  24. 441
  25. 841
  26. 9
  27. 144
  28. 801
  29. 5041
  30. 576
  31. 2809
  32. 5476
  33. 125
  34. 4600
  35. 1156
  36. 4356
  37. 576
  38. 53
  39. 12
  40. 5

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