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Class 8 Maths Worksheet: Algebraic Identities

Maths worksheets lesson 61: Algebraic identities · Set 925 · 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 74².
  2. 2.If a − b = 1 and ab = 132, what is a² + b²?
  3. 3.Find the value of x² − y² when x = 7 and y = 4.
  4. 4.Use (a + b)² = a² + 2ab + b² to find 43².
  5. 5.Use (a + b)² = a² + 2ab + b² to find 106².
  6. 6.Use (a + b)(a − b) = a² − b² to find 76 × 64.
  7. 7.If a + b = 5 and ab = 6, what is a² + b²?
  8. 8.Use (a − b)² = a² − 2ab + b² to find 21².
  9. 9.Use (a + b)² = a² + 2ab + b² to find 86².
  10. 10.Use (a + b)(a − b) = a² − b² to find 99 × 81.
  11. 11.Use (a + b)² = a² + 2ab + b² to find 56².
  12. 12.Find the value of x² − y² when x = 10 and y = 3.
  13. 13.Use (a − b)² = a² − 2ab + b² to find 34².
  14. 14.Use (a + b)² = a² + 2ab + b² to find 68².
  15. 15.Use (a + b)² = a² + 2ab + b² to find 36².
  16. 16.Use a² − b² = (a + b)(a − b) to find 58² − 24².
  17. 17.Use a² − b² = (a + b)(a − b) to find 65² − 50².
  18. 18.Find the value of x² + 2xy + y² when x = 14 and y = 7.
  19. 19.Use (a − b)² = a² − 2ab + b² to find 56².
  20. 20.Use a² − b² = (a + b)(a − b) to find 74² − 12².
  21. 21.If a + b = 12 and ab = 32, what is a² + b²?
  22. 22.Use (a − b)² = a² − 2ab + b² to find 53².
  23. 23.Find the value of x² − y² when x = 5 and y = 2.
  24. 24.Use (a + b)(a − b) = a² − b² to find 95 × 85.
  25. 25.Use (a + b)(a − b) = a² − b² to find 64 × 56.
  26. 26.Use (a − b)² = a² − 2ab + b² to find 81².
  27. 27.Use (a − b)² = a² − 2ab + b² to find 28².
  28. 28.Use (a − b)² = a² − 2ab + b² to find 32².
  29. 29.Use (a + b)² = a² + 2ab + b² to find 33².
  30. 30.Use (a − b)² = a² − 2ab + b² to find 37².
  31. 31.Use (a + b)² = a² + 2ab + b² to find 98².
  32. 32.Use a² − b² = (a + b)(a − b) to find 74² − 64².
  33. 33.Use (a + b)(a − b) = a² − b² to find 69 × 51.
  34. 34.Use a² − b² = (a + b)(a − b) to find 41² − 5².
  35. 35.Find the value of x² − 2xy + y² when x = 8 and y = 5.
  36. 36.Find the value of x² − 2xy + y² when x = 14 and y = 2.
  37. 37.If a + b = 3 and ab = 2, what is a² + b²?
  38. 38.Use (a − b)² = a² − 2ab + b² to find 83².
  39. 39.Use (a − b)² = a² − 2ab + b² to find 69².
  40. 40.Use (a + b)² = a² + 2ab + b² to find 63².

Answer key

  1. 5476
  2. 265
  3. 33
  4. 1849
  5. 11236
  6. 4864
  7. 13
  8. 441
  9. 7396
  10. 8019
  11. 3136
  12. 91
  13. 1156
  14. 4624
  15. 1296
  16. 2788
  17. 1725
  18. 441
  19. 3136
  20. 5332
  21. 80
  22. 2809
  23. 21
  24. 8075
  25. 3584
  26. 6561
  27. 784
  28. 1024
  29. 1089
  30. 1369
  31. 9604
  32. 1380
  33. 3519
  34. 1656
  35. 9
  36. 144
  37. 5
  38. 6889
  39. 4761
  40. 3969

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