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Class 8 Maths Worksheet: Algebraic Identities

Maths worksheets lesson 61: Algebraic identities · Set 967 · 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)(a − b) = a² − b² to find 31 × 29.
  2. 2.Find the value of x² − 2xy + y² when x = 4 and y = 3.
  3. 3.Use (a + b)² = a² + 2ab + b² to find 45².
  4. 4.Find the value of x² − 2xy + y² when x = 13 and y = 10.
  5. 5.Find the value of x² − 2xy + y² when x = 5 and y = 2.
  6. 6.Use (a − b)² = a² − 2ab + b² to find 62².
  7. 7.Use (a + b)(a − b) = a² − b² to find 98 × 82.
  8. 8.Use (a + b)² = a² + 2ab + b² to find 17².
  9. 9.Find the value of x² + 2xy + y² when x = 15 and y = 1.
  10. 10.If a − b = 1 and ab = 12, what is a² + b²?
  11. 11.Use (a − b)² = a² − 2ab + b² to find 71².
  12. 12.Use (a − b)² = a² − 2ab + b² to find 33².
  13. 13.Use (a − b)² = a² − 2ab + b² to find 84².
  14. 14.If a + b = 12 and ab = 32, what is a² + b²?
  15. 15.Use (a − b)² = a² − 2ab + b² to find 27².
  16. 16.If a + b = 12 and ab = 35, what is a² + b²?
  17. 17.Find the value of x² − y² when x = 13 and y = 1.
  18. 18.Use (a + b)² = a² + 2ab + b² to find 76².
  19. 19.Use (a + b)(a − b) = a² − b² to find 51 × 49.
  20. 20.Use (a − b)² = a² − 2ab + b² to find 98².
  21. 21.Find the value of x² − 2xy + y² when x = 4 and y = 2.
  22. 22.Use (a + b)² = a² + 2ab + b² to find 39².
  23. 23.Use (a + b)² = a² + 2ab + b² to find 61².
  24. 24.Use (a + b)² = a² + 2ab + b² to find 41².
  25. 25.Use (a − b)² = a² − 2ab + b² to find 61².
  26. 26.Use a² − b² = (a + b)(a − b) to find 49² − 22².
  27. 27.Find the value of x² − 2xy + y² when x = 11 and y = 1.
  28. 28.Use a² − b² = (a + b)(a − b) to find 26² − 11².
  29. 29.Find the value of x² + 2xy + y² when x = 14 and y = 5.
  30. 30.If a + b = 8 and ab = 12, what is a² + b²?
  31. 31.Find the value of x² − 2xy + y² when x = 4 and y = 1.
  32. 32.Use (a + b)(a − b) = a² − b² to find 48 × 32.
  33. 33.Use (a + b)² = a² + 2ab + b² to find 62².
  34. 34.Use (a + b)(a − b) = a² − b² to find 45 × 35.
  35. 35.Use (a + b)(a − b) = a² − b² to find 55 × 45.
  36. 36.Use (a + b)(a − b) = a² − b² to find 38 × 22.
  37. 37.Use (a + b)(a − b) = a² − b² to find 89 × 71.
  38. 38.If a − b = 3 and ab = 18, what is a² + b²?
  39. 39.Use (a + b)² = a² + 2ab + b² to find 104².
  40. 40.Use a² − b² = (a + b)(a − b) to find 23² − 18².

Answer key

  1. 899
  2. 1
  3. 2025
  4. 9
  5. 9
  6. 3844
  7. 8036
  8. 289
  9. 256
  10. 25
  11. 5041
  12. 1089
  13. 7056
  14. 80
  15. 729
  16. 74
  17. 168
  18. 5776
  19. 2499
  20. 9604
  21. 4
  22. 1521
  23. 3721
  24. 1681
  25. 3721
  26. 1917
  27. 100
  28. 555
  29. 361
  30. 40
  31. 9
  32. 1536
  33. 3844
  34. 1575
  35. 2475
  36. 836
  37. 6319
  38. 45
  39. 10816
  40. 205

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