← Algebraic identities lesson New set →

Class 8 Maths Worksheet: Algebraic Identities

Maths worksheets lesson 61: Algebraic identities · Set 31 · 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 57².
  2. 2.Use (a + b)(a − b) = a² − b² to find 95 × 85.
  3. 3.Use (a + b)² = a² + 2ab + b² to find 48².
  4. 4.Use (a + b)(a − b) = a² − b² to find 107 × 93.
  5. 5.Use (a + b)(a − b) = a² − b² to find 62 × 58.
  6. 6.Use a² − b² = (a + b)(a − b) to find 81² − 49².
  7. 7.Use (a + b)² = a² + 2ab + b² to find 101².
  8. 8.Find the value of x² + 2xy + y² when x = 5 and y = 1.
  9. 9.If a − b = 9 and ab = 36, what is a² + b²?
  10. 10.Use (a + b)(a − b) = a² − b² to find 51 × 49.
  11. 11.Use (a − b)² = a² − 2ab + b² to find 98².
  12. 12.Find the value of x² − 2xy + y² when x = 5 and y = 4.
  13. 13.If a − b = 1 and ab = 20, what is a² + b²?
  14. 14.Use (a − b)² = a² − 2ab + b² to find 76².
  15. 15.If a + b = 10 and ab = 16, what is a² + b²?
  16. 16.If a − b = 7 and ab = 8, what is a² + b²?
  17. 17.Use (a + b)(a − b) = a² − b² to find 49 × 31.
  18. 18.If a − b = 1 and ab = 12, what is a² + b²?
  19. 19.Find the value of x² − y² when x = 8 and y = 1.
  20. 20.Use (a − b)² = a² − 2ab + b² to find 71².
  21. 21.Find the value of x² − y² when x = 7 and y = 1.
  22. 22.Use (a + b)² = a² + 2ab + b² to find 83².
  23. 23.If a + b = 10 and ab = 9, what is a² + b²?
  24. 24.Use (a + b)(a − b) = a² − b² to find 81 × 79.
  25. 25.Use a² − b² = (a + b)(a − b) to find 81² − 71².
  26. 26.If a + b = 4 and ab = 3, what is a² + b²?
  27. 27.If a + b = 11 and ab = 24, what is a² + b²?
  28. 28.Find the value of x² − 2xy + y² when x = 5 and y = 2.
  29. 29.Use (a + b)² = a² + 2ab + b² to find 27².
  30. 30.Use (a + b)² = a² + 2ab + b² to find 22².
  31. 31.Use a² − b² = (a + b)(a − b) to find 44² − 6².
  32. 32.Use a² − b² = (a + b)(a − b) to find 37² − 33².
  33. 33.Use (a − b)² = a² − 2ab + b² to find 61².
  34. 34.If a + b = 9 and ab = 14, what is a² + b²?
  35. 35.If a + b = 16 and ab = 48, what is a² + b²?
  36. 36.Use a² − b² = (a + b)(a − b) to find 69² − 66².
  37. 37.Use (a + b)(a − b) = a² − b² to find 93 × 87.
  38. 38.Use (a + b)² = a² + 2ab + b² to find 13².
  39. 39.Use (a + b)² = a² + 2ab + b² to find 92².
  40. 40.Use a² − b² = (a + b)(a − b) to find 25² − 8².

Answer key

  1. 3249
  2. 8075
  3. 2304
  4. 9951
  5. 3596
  6. 4160
  7. 10201
  8. 36
  9. 153
  10. 2499
  11. 9604
  12. 1
  13. 41
  14. 5776
  15. 68
  16. 65
  17. 1519
  18. 25
  19. 63
  20. 5041
  21. 48
  22. 6889
  23. 82
  24. 6399
  25. 1520
  26. 10
  27. 73
  28. 9
  29. 729
  30. 484
  31. 1900
  32. 280
  33. 3721
  34. 53
  35. 160
  36. 405
  37. 8091
  38. 169
  39. 8464
  40. 561

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