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Class 8 Maths Worksheet: Algebraic Identities

Maths worksheets lesson 61: Algebraic identities · Set 160 · 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 = 12 and y = 4.
  2. 2.Use (a + b)² = a² + 2ab + b² to find 58².
  3. 3.If a − b = 6 and ab = 7, what is a² + b²?
  4. 4.If a + b = 5 and ab = 4, what is a² + b²?
  5. 5.Find the value of x² + 2xy + y² when x = 10 and y = 7.
  6. 6.Use (a + b)(a − b) = a² − b² to find 23 × 17.
  7. 7.Use (a + b)² = a² + 2ab + b² to find 21².
  8. 8.Use (a + b)² = a² + 2ab + b² to find 79².
  9. 9.Use a² − b² = (a + b)(a − b) to find 35² − 2².
  10. 10.Find the value of x² + 2xy + y² when x = 4 and y = 3.
  11. 11.Find the value of x² − y² when x = 8 and y = 2.
  12. 12.Use (a + b)(a − b) = a² − b² to find 97 × 83.
  13. 13.Use (a + b)² = a² + 2ab + b² to find 16².
  14. 14.Use (a + b)² = a² + 2ab + b² to find 68².
  15. 15.Use (a + b)² = a² + 2ab + b² to find 11².
  16. 16.Use (a + b)² = a² + 2ab + b² to find 29².
  17. 17.If a − b = 1 and ab = 6, what is a² + b²?
  18. 18.If a + b = 9 and ab = 20, what is a² + b²?
  19. 19.Use (a + b)(a − b) = a² − b² to find 34 × 26.
  20. 20.Use a² − b² = (a + b)(a − b) to find 85² − 30².
  21. 21.If a − b = 8 and ab = 48, what is a² + b²?
  22. 22.Use a² − b² = (a + b)(a − b) to find 57² − 29².
  23. 23.Use (a + b)² = a² + 2ab + b² to find 31².
  24. 24.Use (a + b)² = a² + 2ab + b² to find 22².
  25. 25.Find the value of x² − 2xy + y² when x = 6 and y = 2.
  26. 26.Use (a − b)² = a² − 2ab + b² to find 91².
  27. 27.If a − b = 2 and ab = 3, what is a² + b²?
  28. 28.Use (a + b)(a − b) = a² − b² to find 35 × 25.
  29. 29.Use (a − b)² = a² − 2ab + b² to find 61².
  30. 30.Use (a + b)² = a² + 2ab + b² to find 102².
  31. 31.Use a² − b² = (a + b)(a − b) to find 33² − 16².
  32. 32.Use (a + b)² = a² + 2ab + b² to find 43².
  33. 33.Use (a + b)(a − b) = a² − b² to find 37 × 23.
  34. 34.Use a² − b² = (a + b)(a − b) to find 21² − 2².
  35. 35.Use (a − b)² = a² − 2ab + b² to find 22².
  36. 36.Find the value of x² + 2xy + y² when x = 11 and y = 7.
  37. 37.Use (a − b)² = a² − 2ab + b² to find 19².
  38. 38.Use (a − b)² = a² − 2ab + b² to find 69².
  39. 39.Use a² − b² = (a + b)(a − b) to find 45² − 22².
  40. 40.Use (a − b)² = a² − 2ab + b² to find 54².

Answer key

  1. 64
  2. 3364
  3. 50
  4. 17
  5. 289
  6. 391
  7. 441
  8. 6241
  9. 1221
  10. 49
  11. 60
  12. 8051
  13. 256
  14. 4624
  15. 121
  16. 841
  17. 13
  18. 41
  19. 884
  20. 6325
  21. 160
  22. 2408
  23. 961
  24. 484
  25. 16
  26. 8281
  27. 10
  28. 875
  29. 3721
  30. 10404
  31. 833
  32. 1849
  33. 851
  34. 437
  35. 484
  36. 324
  37. 361
  38. 4761
  39. 1541
  40. 2916

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