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Class 8 Maths Worksheet: Algebraic Identities

Maths worksheets lesson 61: Algebraic identities · Set 585 · 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 a² − b² = (a + b)(a − b) to find 94² − 37².
  2. 2.If a + b = 14 and ab = 48, what is a² + b²?
  3. 3.Use (a − b)² = a² − 2ab + b² to find 47².
  4. 4.Use (a − b)² = a² − 2ab + b² to find 87².
  5. 5.Find the value of x² + 2xy + y² when x = 3 and y = 2.
  6. 6.If a + b = 12 and ab = 35, what is a² + b²?
  7. 7.If a − b = 6 and ab = 55, what is a² + b²?
  8. 8.Use a² − b² = (a + b)(a − b) to find 26² − 8².
  9. 9.Find the value of x² + 2xy + y² when x = 5 and y = 1.
  10. 10.Use (a − b)² = a² − 2ab + b² to find 45².
  11. 11.If a + b = 20 and ab = 96, what is a² + b²?
  12. 12.Use a² − b² = (a + b)(a − b) to find 97² − 96².
  13. 13.Use (a + b)(a − b) = a² − b² to find 74 × 66.
  14. 14.Use (a − b)² = a² − 2ab + b² to find 95².
  15. 15.Find the value of x² + 2xy + y² when x = 13 and y = 3.
  16. 16.Use (a + b)² = a² + 2ab + b² to find 45².
  17. 17.Use (a − b)² = a² − 2ab + b² to find 25².
  18. 18.Find the value of x² + 2xy + y² when x = 14 and y = 11.
  19. 19.Find the value of x² + 2xy + y² when x = 10 and y = 3.
  20. 20.Find the value of x² + 2xy + y² when x = 15 and y = 1.
  21. 21.If a − b = 11 and ab = 12, what is a² + b²?
  22. 22.If a + b = 6 and ab = 8, what is a² + b²?
  23. 23.If a + b = 11 and ab = 10, what is a² + b²?
  24. 24.Use (a − b)² = a² − 2ab + b² to find 56².
  25. 25.If a − b = 10 and ab = 24, what is a² + b²?
  26. 26.Use (a + b)² = a² + 2ab + b² to find 71².
  27. 27.Use a² − b² = (a + b)(a − b) to find 41² − 17².
  28. 28.Use (a + b)² = a² + 2ab + b² to find 16².
  29. 29.Use a² − b² = (a + b)(a − b) to find 36² − 18².
  30. 30.Find the value of x² + 2xy + y² when x = 4 and y = 2.
  31. 31.Use (a + b)² = a² + 2ab + b² to find 76².
  32. 32.Use (a − b)² = a² − 2ab + b² to find 16².
  33. 33.Use (a − b)² = a² − 2ab + b² to find 65².
  34. 34.Use (a − b)² = a² − 2ab + b² to find 28².
  35. 35.Find the value of x² − 2xy + y² when x = 10 and y = 6.
  36. 36.Use (a + b)² = a² + 2ab + b² to find 26².
  37. 37.Find the value of x² + 2xy + y² when x = 4 and y = 1.
  38. 38.Use (a + b)(a − b) = a² − b² to find 106 × 94.
  39. 39.Use a² − b² = (a + b)(a − b) to find 36² − 26².
  40. 40.Use (a + b)² = a² + 2ab + b² to find 17².

Answer key

  1. 7467
  2. 100
  3. 2209
  4. 7569
  5. 25
  6. 74
  7. 146
  8. 612
  9. 36
  10. 2025
  11. 208
  12. 193
  13. 4884
  14. 9025
  15. 256
  16. 2025
  17. 625
  18. 625
  19. 169
  20. 256
  21. 145
  22. 20
  23. 101
  24. 3136
  25. 148
  26. 5041
  27. 1392
  28. 256
  29. 972
  30. 36
  31. 5776
  32. 256
  33. 4225
  34. 784
  35. 16
  36. 676
  37. 25
  38. 9964
  39. 620
  40. 289

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