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Class 8 Maths Worksheet: Algebraic Identities

Maths worksheets lesson 61: Algebraic identities · Set 166 · 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.Find the value of x² − y² when x = 4 and y = 2.
  2. 2.Use (a − b)² = a² − 2ab + b² to find 11².
  3. 3.Find the value of x² + 2xy + y² when x = 3 and y = 2.
  4. 4.Use a² − b² = (a + b)(a − b) to find 76² − 19².
  5. 5.Use (a − b)² = a² − 2ab + b² to find 57².
  6. 6.Find the value of x² + 2xy + y² when x = 6 and y = 5.
  7. 7.Use (a + b)(a − b) = a² − b² to find 24 × 16.
  8. 8.Find the value of x² − y² when x = 4 and y = 3.
  9. 9.Find the value of x² − y² when x = 10 and y = 7.
  10. 10.Use a² − b² = (a + b)(a − b) to find 75² − 54².
  11. 11.Use (a + b)² = a² + 2ab + b² to find 52².
  12. 12.Use (a + b)² = a² + 2ab + b² to find 48².
  13. 13.Use (a + b)² = a² + 2ab + b² to find 36².
  14. 14.Find the value of x² + 2xy + y² when x = 13 and y = 3.
  15. 15.Use (a + b)² = a² + 2ab + b² to find 41².
  16. 16.Use (a + b)² = a² + 2ab + b² to find 31².
  17. 17.Use (a − b)² = a² − 2ab + b² to find 68².
  18. 18.Use (a − b)² = a² − 2ab + b² to find 18².
  19. 19.Use (a + b)(a − b) = a² − b² to find 23 × 17.
  20. 20.Use (a + b)² = a² + 2ab + b² to find 13².
  21. 21.Use (a + b)(a − b) = a² − b² to find 93 × 87.
  22. 22.Use (a + b)(a − b) = a² − b² to find 53 × 47.
  23. 23.Use (a − b)² = a² − 2ab + b² to find 13².
  24. 24.If a − b = 2 and ab = 3, what is a² + b²?
  25. 25.Use (a − b)² = a² − 2ab + b² to find 88².
  26. 26.Use (a − b)² = a² − 2ab + b² to find 39².
  27. 27.Use (a + b)² = a² + 2ab + b² to find 78².
  28. 28.If a − b = 8 and ab = 48, what is a² + b²?
  29. 29.Use (a + b)(a − b) = a² − b² to find 97 × 83.
  30. 30.If a + b = 11 and ab = 10, what is a² + b²?
  31. 31.Use a² − b² = (a + b)(a − b) to find 54² − 1².
  32. 32.Use (a − b)² = a² − 2ab + b² to find 77².
  33. 33.Use a² − b² = (a + b)(a − b) to find 83² − 29².
  34. 34.If a + b = 8 and ab = 7, what is a² + b²?
  35. 35.Use (a + b)(a − b) = a² − b² to find 108 × 92.
  36. 36.Use (a + b)(a − b) = a² − b² to find 91 × 89.
  37. 37.If a − b = 2 and ab = 8, what is a² + b²?
  38. 38.Use (a + b)(a − b) = a² − b² to find 62 × 58.
  39. 39.Use (a − b)² = a² − 2ab + b² to find 66².
  40. 40.Use (a + b)² = a² + 2ab + b² to find 96².

Answer key

  1. 12
  2. 121
  3. 25
  4. 5415
  5. 3249
  6. 121
  7. 384
  8. 7
  9. 51
  10. 2709
  11. 2704
  12. 2304
  13. 1296
  14. 256
  15. 1681
  16. 961
  17. 4624
  18. 324
  19. 391
  20. 169
  21. 8091
  22. 2491
  23. 169
  24. 10
  25. 7744
  26. 1521
  27. 6084
  28. 160
  29. 8051
  30. 101
  31. 2915
  32. 5929
  33. 6048
  34. 50
  35. 9936
  36. 8099
  37. 20
  38. 3596
  39. 4356
  40. 9216

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