← Algebraic identities lesson New set →

Class 8 Maths Worksheet: Algebraic Identities

Maths worksheets lesson 61: Algebraic identities · Set 666 · 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 = 10 and ab = 11, what is a² + b²?
  2. 2.Find the value of x² + 2xy + y² when x = 4 and y = 1.
  3. 3.Use (a − b)² = a² − 2ab + b² to find 78².
  4. 4.Find the value of x² − y² when x = 9 and y = 6.
  5. 5.If a − b = 1 and ab = 42, what is a² + b²?
  6. 6.Find the value of x² − 2xy + y² when x = 14 and y = 10.
  7. 7.Use (a + b)² = a² + 2ab + b² to find 85².
  8. 8.Find the value of x² − y² when x = 12 and y = 2.
  9. 9.Find the value of x² + 2xy + y² when x = 7 and y = 1.
  10. 10.Use (a − b)² = a² − 2ab + b² to find 96².
  11. 11.Find the value of x² − y² when x = 8 and y = 1.
  12. 12.Use (a − b)² = a² − 2ab + b² to find 79².
  13. 13.If a − b = 9 and ab = 10, what is a² + b²?
  14. 14.If a − b = 3 and ab = 10, what is a² + b²?
  15. 15.If a + b = 17 and ab = 60, what is a² + b²?
  16. 16.Use (a + b)² = a² + 2ab + b² to find 76².
  17. 17.Use a² − b² = (a + b)(a − b) to find 63² − 60².
  18. 18.Find the value of x² + 2xy + y² when x = 11 and y = 8.
  19. 19.Use a² − b² = (a + b)(a − b) to find 52² − 37².
  20. 20.Find the value of x² + 2xy + y² when x = 4 and y = 2.
  21. 21.Use a² − b² = (a + b)(a − b) to find 84² − 45².
  22. 22.Use (a − b)² = a² − 2ab + b² to find 39².
  23. 23.Use (a + b)(a − b) = a² − b² to find 69 × 51.
  24. 24.Use (a − b)² = a² − 2ab + b² to find 21².
  25. 25.Use (a − b)² = a² − 2ab + b² to find 34².
  26. 26.Find the value of x² + 2xy + y² when x = 8 and y = 4.
  27. 27.If a + b = 19 and ab = 84, what is a² + b²?
  28. 28.Use (a − b)² = a² − 2ab + b² to find 22².
  29. 29.Use (a + b)² = a² + 2ab + b² to find 102².
  30. 30.Use (a − b)² = a² − 2ab + b² to find 45².
  31. 31.Use (a + b)² = a² + 2ab + b² to find 16².
  32. 32.If a − b = 3 and ab = 70, what is a² + b²?
  33. 33.If a − b = 6 and ab = 7, what is a² + b²?
  34. 34.Find the value of x² + 2xy + y² when x = 11 and y = 4.
  35. 35.Use (a − b)² = a² − 2ab + b² to find 85².
  36. 36.Find the value of x² − y² when x = 4 and y = 2.
  37. 37.Use (a − b)² = a² − 2ab + b² to find 83².
  38. 38.Use (a + b)² = a² + 2ab + b² to find 53².
  39. 39.Use a² − b² = (a + b)(a − b) to find 73² − 56².
  40. 40.Find the value of x² − y² when x = 13 and y = 5.

Answer key

  1. 122
  2. 25
  3. 6084
  4. 45
  5. 85
  6. 16
  7. 7225
  8. 140
  9. 64
  10. 9216
  11. 63
  12. 6241
  13. 101
  14. 29
  15. 169
  16. 5776
  17. 369
  18. 361
  19. 1335
  20. 36
  21. 5031
  22. 1521
  23. 3519
  24. 441
  25. 1156
  26. 144
  27. 193
  28. 484
  29. 10404
  30. 2025
  31. 256
  32. 149
  33. 50
  34. 225
  35. 7225
  36. 12
  37. 6889
  38. 2809
  39. 2193
  40. 144

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