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Class 8 Maths Worksheet: Algebraic Identities

Maths worksheets lesson 61: Algebraic identities · Set 600 · 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 − y² when x = 11 and y = 7.
  2. 2.Use (a − b)² = a² − 2ab + b² to find 75².
  3. 3.Use (a + b)(a − b) = a² − b² to find 66 × 54.
  4. 4.Use (a + b)(a − b) = a² − b² to find 107 × 93.
  5. 5.Use (a − b)² = a² − 2ab + b² to find 49².
  6. 6.If a − b = 5 and ab = 24, what is a² + b²?
  7. 7.Use (a + b)(a − b) = a² − b² to find 57 × 43.
  8. 8.If a − b = 2 and ab = 3, what is a² + b²?
  9. 9.Use (a + b)² = a² + 2ab + b² to find 95².
  10. 10.If a − b = 1 and ab = 2, what is a² + b²?
  11. 11.If a − b = 5 and ab = 14, what is a² + b²?
  12. 12.Use (a − b)² = a² − 2ab + b² to find 17².
  13. 13.Find the value of x² + 2xy + y² when x = 6 and y = 4.
  14. 14.Use (a + b)(a − b) = a² − b² to find 28 × 12.
  15. 15.If a − b = 3 and ab = 54, what is a² + b²?
  16. 16.Use (a + b)(a − b) = a² − b² to find 55 × 45.
  17. 17.Use (a + b)² = a² + 2ab + b² to find 89².
  18. 18.Use (a + b)² = a² + 2ab + b² to find 34².
  19. 19.Use a² − b² = (a + b)(a − b) to find 78² − 1².
  20. 20.Use (a + b)² = a² + 2ab + b² to find 57².
  21. 21.If a − b = 3 and ab = 18, what is a² + b²?
  22. 22.If a − b = 10 and ab = 24, what is a² + b²?
  23. 23.Find the value of x² + 2xy + y² when x = 15 and y = 11.
  24. 24.Find the value of x² − 2xy + y² when x = 5 and y = 2.
  25. 25.Use (a + b)² = a² + 2ab + b² to find 32².
  26. 26.Find the value of x² + 2xy + y² when x = 12 and y = 4.
  27. 27.If a − b = 2 and ab = 8, what is a² + b²?
  28. 28.Use (a − b)² = a² − 2ab + b² to find 39².
  29. 29.Use a² − b² = (a + b)(a − b) to find 27² − 11².
  30. 30.Use a² − b² = (a + b)(a − b) to find 27² − 5².
  31. 31.Use (a + b)(a − b) = a² − b² to find 71 × 69.
  32. 32.Use (a + b)² = a² + 2ab + b² to find 49².
  33. 33.Use (a − b)² = a² − 2ab + b² to find 54².
  34. 34.Find the value of x² − 2xy + y² when x = 14 and y = 12.
  35. 35.Use (a + b)² = a² + 2ab + b² to find 101².
  36. 36.Use a² − b² = (a + b)(a − b) to find 91² − 8².
  37. 37.Find the value of x² − 2xy + y² when x = 3 and y = 2.
  38. 38.Find the value of x² + 2xy + y² when x = 3 and y = 1.
  39. 39.Use (a + b)² = a² + 2ab + b² to find 55².
  40. 40.Use a² − b² = (a + b)(a − b) to find 59² − 18².

Answer key

  1. 72
  2. 5625
  3. 3564
  4. 9951
  5. 2401
  6. 73
  7. 2451
  8. 10
  9. 9025
  10. 5
  11. 53
  12. 289
  13. 100
  14. 336
  15. 117
  16. 2475
  17. 7921
  18. 1156
  19. 6083
  20. 3249
  21. 45
  22. 148
  23. 676
  24. 9
  25. 1024
  26. 256
  27. 20
  28. 1521
  29. 608
  30. 704
  31. 4899
  32. 2401
  33. 2916
  34. 4
  35. 10201
  36. 8217
  37. 1
  38. 16
  39. 3025
  40. 3157

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