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Class 8 Maths Worksheet: Algebraic Identities

Maths worksheets lesson 61: Algebraic identities · Set 861 · 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 + 2xy + y² when x = 11 and y = 1.
  2. 2.Use a² − b² = (a + b)(a − b) to find 49² − 8².
  3. 3.If a − b = 2 and ab = 15, what is a² + b²?
  4. 4.Use a² − b² = (a + b)(a − b) to find 81² − 5².
  5. 5.Use (a + b)² = a² + 2ab + b² to find 102².
  6. 6.Use (a + b)(a − b) = a² − b² to find 82 × 78.
  7. 7.Use (a + b)(a − b) = a² − b² to find 98 × 82.
  8. 8.Use (a + b)(a − b) = a² − b² to find 25 × 15.
  9. 9.Use (a − b)² = a² − 2ab + b² to find 13².
  10. 10.Use a² − b² = (a + b)(a − b) to find 44² − 18².
  11. 11.Find the value of x² − 2xy + y² when x = 7 and y = 6.
  12. 12.Use (a + b)² = a² + 2ab + b² to find 57².
  13. 13.Use (a − b)² = a² − 2ab + b² to find 56².
  14. 14.Use a² − b² = (a + b)(a − b) to find 31² − 7².
  15. 15.Use a² − b² = (a + b)(a − b) to find 34² − 20².
  16. 16.Find the value of x² + 2xy + y² when x = 9 and y = 4.
  17. 17.Use a² − b² = (a + b)(a − b) to find 29² − 8².
  18. 18.Use (a + b)(a − b) = a² − b² to find 59 × 41.
  19. 19.Use (a + b)² = a² + 2ab + b² to find 32².
  20. 20.Find the value of x² − y² when x = 3 and y = 1.
  21. 21.If a − b = 9 and ab = 10, what is a² + b²?
  22. 22.Use a² − b² = (a + b)(a − b) to find 27² − 1².
  23. 23.Use (a + b)(a − b) = a² − b² to find 97 × 83.
  24. 24.If a − b = 1 and ab = 12, what is a² + b²?
  25. 25.Use (a + b)² = a² + 2ab + b² to find 16².
  26. 26.If a + b = 3 and ab = 2, what is a² + b²?
  27. 27.Find the value of x² + 2xy + y² when x = 8 and y = 1.
  28. 28.If a − b = 6 and ab = 7, what is a² + b²?
  29. 29.Use a² − b² = (a + b)(a − b) to find 66² − 47².
  30. 30.Use (a − b)² = a² − 2ab + b² to find 34².
  31. 31.Use (a − b)² = a² − 2ab + b² to find 39².
  32. 32.Use (a + b)² = a² + 2ab + b² to find 24².
  33. 33.Use (a + b)² = a² + 2ab + b² to find 77².
  34. 34.Use (a + b)(a − b) = a² − b² to find 61 × 59.
  35. 35.Use (a − b)² = a² − 2ab + b² to find 96².
  36. 36.Use (a + b)(a − b) = a² − b² to find 99 × 81.
  37. 37.If a + b = 19 and ab = 88, what is a² + b²?
  38. 38.Use a² − b² = (a + b)(a − b) to find 97² − 7².
  39. 39.Use (a + b)² = a² + 2ab + b² to find 54².
  40. 40.Use (a − b)² = a² − 2ab + b² to find 97².

Answer key

  1. 144
  2. 2337
  3. 34
  4. 6536
  5. 10404
  6. 6396
  7. 8036
  8. 375
  9. 169
  10. 1612
  11. 1
  12. 3249
  13. 3136
  14. 912
  15. 756
  16. 169
  17. 777
  18. 2419
  19. 1024
  20. 8
  21. 101
  22. 728
  23. 8051
  24. 25
  25. 256
  26. 5
  27. 81
  28. 50
  29. 2147
  30. 1156
  31. 1521
  32. 576
  33. 5929
  34. 3599
  35. 9216
  36. 8019
  37. 185
  38. 9360
  39. 2916
  40. 9409

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