← Algebraic identities lesson New set →

Class 8 Maths Worksheet: Algebraic Identities

Maths worksheets lesson 61: Algebraic identities · Set 826 · 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 + 2xy + y² when x = 11 and y = 8.
  2. 2.Use a² − b² = (a + b)(a − b) to find 84² − 21².
  3. 3.Use a² − b² = (a + b)(a − b) to find 62² − 53².
  4. 4.Find the value of x² + 2xy + y² when x = 12 and y = 7.
  5. 5.If a − b = 2 and ab = 8, what is a² + b²?
  6. 6.Use (a − b)² = a² − 2ab + b² to find 31².
  7. 7.Use (a − b)² = a² − 2ab + b² to find 29².
  8. 8.Use a² − b² = (a + b)(a − b) to find 56² − 44².
  9. 9.Use a² − b² = (a + b)(a − b) to find 50² − 30².
  10. 10.Use a² − b² = (a + b)(a − b) to find 21² − 19².
  11. 11.Use (a + b)(a − b) = a² − b² to find 81 × 79.
  12. 12.Use (a − b)² = a² − 2ab + b² to find 22².
  13. 13.Find the value of x² − 2xy + y² when x = 13 and y = 12.
  14. 14.Use a² − b² = (a + b)(a − b) to find 60² − 15².
  15. 15.Use (a + b)² = a² + 2ab + b² to find 98².
  16. 16.Use (a + b)² = a² + 2ab + b² to find 79².
  17. 17.Use (a + b)² = a² + 2ab + b² to find 95².
  18. 18.Use (a + b)² = a² + 2ab + b² to find 62².
  19. 19.Find the value of x² − 2xy + y² when x = 9 and y = 5.
  20. 20.Use (a + b)² = a² + 2ab + b² to find 13².
  21. 21.Use (a + b)² = a² + 2ab + b² to find 44².
  22. 22.Find the value of x² − y² when x = 3 and y = 1.
  23. 23.Use (a + b)² = a² + 2ab + b² to find 61².
  24. 24.Use (a − b)² = a² − 2ab + b² to find 12².
  25. 25.Use a² − b² = (a + b)(a − b) to find 67² − 54².
  26. 26.Use (a − b)² = a² − 2ab + b² to find 27².
  27. 27.If a + b = 5 and ab = 6, what is a² + b²?
  28. 28.Find the value of x² − y² when x = 10 and y = 5.
  29. 29.If a + b = 9 and ab = 20, what is a² + b²?
  30. 30.Use (a + b)² = a² + 2ab + b² to find 57².
  31. 31.Use a² − b² = (a + b)(a − b) to find 26² − 7².
  32. 32.Find the value of x² + 2xy + y² when x = 3 and y = 1.
  33. 33.Use (a − b)² = a² − 2ab + b² to find 62².
  34. 34.Use (a + b)(a − b) = a² − b² to find 39 × 21.
  35. 35.Find the value of x² − y² when x = 13 and y = 2.
  36. 36.Use a² − b² = (a + b)(a − b) to find 82² − 73².
  37. 37.Use a² − b² = (a + b)(a − b) to find 86² − 12².
  38. 38.If a − b = 5 and ab = 50, what is a² + b²?
  39. 39.Use (a + b)(a − b) = a² − b² to find 55 × 45.
  40. 40.If a + b = 11 and ab = 30, what is a² + b²?

Answer key

  1. 361
  2. 6615
  3. 1035
  4. 361
  5. 20
  6. 961
  7. 841
  8. 1200
  9. 1600
  10. 80
  11. 6399
  12. 484
  13. 1
  14. 3375
  15. 9604
  16. 6241
  17. 9025
  18. 3844
  19. 16
  20. 169
  21. 1936
  22. 8
  23. 3721
  24. 144
  25. 1573
  26. 729
  27. 13
  28. 75
  29. 41
  30. 3249
  31. 627
  32. 16
  33. 3844
  34. 819
  35. 165
  36. 1395
  37. 7252
  38. 125
  39. 2475
  40. 61

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