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Class 8 Maths Worksheet: Algebraic Identities

Maths worksheets lesson 61: Algebraic identities · Set 232 · 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.Use (a + b)² = a² + 2ab + b² to find 46².
  2. 2.Use (a − b)² = a² − 2ab + b² to find 48².
  3. 3.Use (a + b)² = a² + 2ab + b² to find 43².
  4. 4.Find the value of x² − 2xy + y² when x = 9 and y = 2.
  5. 5.Use (a − b)² = a² − 2ab + b² to find 93².
  6. 6.Use (a + b)² = a² + 2ab + b² to find 45².
  7. 7.If a + b = 7 and ab = 12, what is a² + b²?
  8. 8.Use a² − b² = (a + b)(a − b) to find 48² − 36².
  9. 9.Use (a + b)(a − b) = a² − b² to find 28 × 12.
  10. 10.Use a² − b² = (a + b)(a − b) to find 57² − 10².
  11. 11.Use (a − b)² = a² − 2ab + b² to find 42².
  12. 12.If a − b = 3 and ab = 54, what is a² + b²?
  13. 13.If a + b = 9 and ab = 14, what is a² + b²?
  14. 14.If a − b = 3 and ab = 4, what is a² + b²?
  15. 15.Use (a − b)² = a² − 2ab + b² to find 26².
  16. 16.Use (a − b)² = a² − 2ab + b² to find 27².
  17. 17.Use (a + b)(a − b) = a² − b² to find 34 × 26.
  18. 18.If a + b = 10 and ab = 24, what is a² + b²?
  19. 19.Use (a + b)² = a² + 2ab + b² to find 54².
  20. 20.Find the value of x² − y² when x = 12 and y = 1.
  21. 21.If a − b = 7 and ab = 30, what is a² + b²?
  22. 22.Use (a + b)(a − b) = a² − b² to find 72 × 68.
  23. 23.Use (a − b)² = a² − 2ab + b² to find 57².
  24. 24.Use (a + b)(a − b) = a² − b² to find 56 × 44.
  25. 25.Find the value of x² − y² when x = 6 and y = 1.
  26. 26.Use (a + b)(a − b) = a² − b² to find 76 × 64.
  27. 27.Find the value of x² + 2xy + y² when x = 5 and y = 4.
  28. 28.If a − b = 2 and ab = 80, what is a² + b²?
  29. 29.Use (a + b)² = a² + 2ab + b² to find 49².
  30. 30.Use a² − b² = (a + b)(a − b) to find 37² − 15².
  31. 31.Use a² − b² = (a + b)(a − b) to find 26² − 1².
  32. 32.Use (a + b)² = a² + 2ab + b² to find 16².
  33. 33.Use a² − b² = (a + b)(a − b) to find 22² − 14².
  34. 34.Use (a + b)² = a² + 2ab + b² to find 48².
  35. 35.If a + b = 16 and ab = 48, what is a² + b²?
  36. 36.Find the value of x² + 2xy + y² when x = 13 and y = 4.
  37. 37.Use (a − b)² = a² − 2ab + b² to find 31².
  38. 38.Find the value of x² + 2xy + y² when x = 8 and y = 5.
  39. 39.Use a² − b² = (a + b)(a − b) to find 39² − 8².
  40. 40.Find the value of x² − 2xy + y² when x = 15 and y = 7.

Answer key

  1. 2116
  2. 2304
  3. 1849
  4. 49
  5. 8649
  6. 2025
  7. 25
  8. 1008
  9. 336
  10. 3149
  11. 1764
  12. 117
  13. 53
  14. 17
  15. 676
  16. 729
  17. 884
  18. 52
  19. 2916
  20. 143
  21. 109
  22. 4896
  23. 3249
  24. 2464
  25. 35
  26. 4864
  27. 81
  28. 164
  29. 2401
  30. 1144
  31. 675
  32. 256
  33. 288
  34. 2304
  35. 160
  36. 289
  37. 961
  38. 169
  39. 1457
  40. 64

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