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Class 8 Maths Worksheet: Algebraic Identities

Maths worksheets lesson 61: Algebraic identities · Set 902 · 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 86².
  2. 2.Use a² − b² = (a + b)(a − b) to find 84² − 59².
  3. 3.If a − b = 3 and ab = 10, what is a² + b²?
  4. 4.Use (a − b)² = a² − 2ab + b² to find 31².
  5. 5.If a − b = 4 and ab = 21, what is a² + b²?
  6. 6.Use (a − b)² = a² − 2ab + b² to find 97².
  7. 7.Use (a + b)² = a² + 2ab + b² to find 34².
  8. 8.If a − b = 1 and ab = 42, what is a² + b²?
  9. 9.Use a² − b² = (a + b)(a − b) to find 94² − 80².
  10. 10.If a − b = 6 and ab = 16, what is a² + b²?
  11. 11.Use (a − b)² = a² − 2ab + b² to find 29².
  12. 12.Use (a + b)(a − b) = a² − b² to find 57 × 43.
  13. 13.Find the value of x² − 2xy + y² when x = 10 and y = 5.
  14. 14.Find the value of x² − 2xy + y² when x = 6 and y = 3.
  15. 15.If a − b = 6 and ab = 40, what is a² + b²?
  16. 16.Use (a − b)² = a² − 2ab + b² to find 45².
  17. 17.Use (a − b)² = a² − 2ab + b² to find 81².
  18. 18.Use (a + b)(a − b) = a² − b² to find 39 × 21.
  19. 19.Find the value of x² − y² when x = 4 and y = 1.
  20. 20.Use a² − b² = (a + b)(a − b) to find 74² − 53².
  21. 21.If a − b = 1 and ab = 2, what is a² + b²?
  22. 22.If a − b = 7 and ab = 8, what is a² + b²?
  23. 23.Find the value of x² + 2xy + y² when x = 11 and y = 8.
  24. 24.Use a² − b² = (a + b)(a − b) to find 27² − 14².
  25. 25.Use (a − b)² = a² − 2ab + b² to find 69².
  26. 26.If a + b = 3 and ab = 2, what is a² + b²?
  27. 27.If a − b = 5 and ab = 50, what is a² + b²?
  28. 28.Use (a − b)² = a² − 2ab + b² to find 53².
  29. 29.Use (a + b)(a − b) = a² − b² to find 29 × 11.
  30. 30.Use (a + b)² = a² + 2ab + b² to find 45².
  31. 31.If a − b = 1 and ab = 12, what is a² + b²?
  32. 32.Use (a + b)(a − b) = a² − b² to find 41 × 39.
  33. 33.Find the value of x² − 2xy + y² when x = 9 and y = 4.
  34. 34.Use (a + b)² = a² + 2ab + b² to find 76².
  35. 35.Use (a + b)² = a² + 2ab + b² to find 12².
  36. 36.Use (a + b)² = a² + 2ab + b² to find 71².
  37. 37.Find the value of x² + 2xy + y² when x = 14 and y = 12.
  38. 38.Use a² − b² = (a + b)(a − b) to find 24² − 3².
  39. 39.Use (a + b)² = a² + 2ab + b² to find 106².
  40. 40.Use a² − b² = (a + b)(a − b) to find 62² − 17².

Answer key

  1. 7396
  2. 3575
  3. 29
  4. 961
  5. 58
  6. 9409
  7. 1156
  8. 85
  9. 2436
  10. 68
  11. 841
  12. 2451
  13. 25
  14. 9
  15. 116
  16. 2025
  17. 6561
  18. 819
  19. 15
  20. 2667
  21. 5
  22. 65
  23. 361
  24. 533
  25. 4761
  26. 5
  27. 125
  28. 2809
  29. 319
  30. 2025
  31. 25
  32. 1599
  33. 25
  34. 5776
  35. 144
  36. 5041
  37. 676
  38. 567
  39. 11236
  40. 3555

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