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Class 8 Maths Worksheet: Algebraic Identities

Maths worksheets lesson 61: Algebraic identities · Set 443 · 40 sums
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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.If a + b = 15 and ab = 36, what is a² + b²?
  2. 2.Use (a + b)² = a² + 2ab + b² to find 73².
  3. 3.Use (a + b)² = a² + 2ab + b² to find 41².
  4. 4.Use a² − b² = (a + b)(a − b) to find 54² − 7².
  5. 5.Use (a + b)² = a² + 2ab + b² to find 79².
  6. 6.Use (a − b)² = a² − 2ab + b² to find 22².
  7. 7.Use (a − b)² = a² − 2ab + b² to find 34².
  8. 8.Use (a − b)² = a² − 2ab + b² to find 36².
  9. 9.Use (a + b)² = a² + 2ab + b² to find 108².
  10. 10.If a + b = 5 and ab = 4, what is a² + b²?
  11. 11.Use (a + b)² = a² + 2ab + b² to find 102².
  12. 12.Use a² − b² = (a + b)(a − b) to find 69² − 20².
  13. 13.Use (a + b)² = a² + 2ab + b² to find 84².
  14. 14.Use (a − b)² = a² − 2ab + b² to find 49².
  15. 15.Use (a − b)² = a² − 2ab + b² to find 35².
  16. 16.Use (a + b)² = a² + 2ab + b² to find 26².
  17. 17.Find the value of x² + 2xy + y² when x = 14 and y = 6.
  18. 18.Find the value of x² − 2xy + y² when x = 3 and y = 2.
  19. 19.Use (a + b)(a − b) = a² − b² to find 51 × 49.
  20. 20.Find the value of x² + 2xy + y² when x = 8 and y = 6.
  21. 21.Use (a + b)(a − b) = a² − b² to find 33 × 27.
  22. 22.If a + b = 22 and ab = 120, what is a² + b²?
  23. 23.Use (a + b)(a − b) = a² − b² to find 99 × 81.
  24. 24.Use (a + b)² = a² + 2ab + b² to find 54².
  25. 25.Find the value of x² − 2xy + y² when x = 10 and y = 8.
  26. 26.If a + b = 15 and ab = 54, what is a² + b²?
  27. 27.If a − b = 2 and ab = 8, what is a² + b²?
  28. 28.Use a² − b² = (a + b)(a − b) to find 33² − 6².
  29. 29.Use (a + b)² = a² + 2ab + b² to find 24².
  30. 30.Use (a + b)(a − b) = a² − b² to find 62 × 58.
  31. 31.Use a² − b² = (a + b)(a − b) to find 88² − 10².
  32. 32.Use (a − b)² = a² − 2ab + b² to find 24².
  33. 33.Find the value of x² − y² when x = 5 and y = 2.
  34. 34.If a − b = 8 and ab = 9, what is a² + b²?
  35. 35.Use (a + b)(a − b) = a² − b² to find 75 × 65.
  36. 36.If a − b = 1 and ab = 6, what is a² + b²?
  37. 37.Find the value of x² − 2xy + y² when x = 7 and y = 1.
  38. 38.Use (a − b)² = a² − 2ab + b² to find 65².
  39. 39.Use (a + b)² = a² + 2ab + b² to find 36².
  40. 40.Find the value of x² − 2xy + y² when x = 11 and y = 3.

Answer key

  1. 153
  2. 5329
  3. 1681
  4. 2867
  5. 6241
  6. 484
  7. 1156
  8. 1296
  9. 11664
  10. 17
  11. 10404
  12. 4361
  13. 7056
  14. 2401
  15. 1225
  16. 676
  17. 400
  18. 1
  19. 2499
  20. 196
  21. 891
  22. 244
  23. 8019
  24. 2916
  25. 4
  26. 117
  27. 20
  28. 1053
  29. 576
  30. 3596
  31. 7644
  32. 576
  33. 21
  34. 82
  35. 4875
  36. 13
  37. 36
  38. 4225
  39. 1296
  40. 64

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