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Class 8 Maths Worksheet: Algebraic Identities

Maths worksheets lesson 61: Algebraic identities · Set 940 · 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.Use a² − b² = (a + b)(a − b) to find 52² − 37².
  2. 2.Use (a + b)² = a² + 2ab + b² to find 36².
  3. 3.Find the value of x² + 2xy + y² when x = 8 and y = 1.
  4. 4.Use (a − b)² = a² − 2ab + b² to find 25².
  5. 5.Use (a + b)(a − b) = a² − b² to find 32 × 28.
  6. 6.Use (a − b)² = a² − 2ab + b² to find 58².
  7. 7.Use (a + b)² = a² + 2ab + b² to find 16².
  8. 8.Use (a + b)² = a² + 2ab + b² to find 48².
  9. 9.Use (a − b)² = a² − 2ab + b² to find 32².
  10. 10.Use (a + b)² = a² + 2ab + b² to find 59².
  11. 11.Find the value of x² − 2xy + y² when x = 8 and y = 1.
  12. 12.Use (a − b)² = a² − 2ab + b² to find 72².
  13. 13.Use (a + b)² = a² + 2ab + b² to find 24².
  14. 14.Use (a − b)² = a² − 2ab + b² to find 51².
  15. 15.Use (a − b)² = a² − 2ab + b² to find 69².
  16. 16.Use (a − b)² = a² − 2ab + b² to find 31².
  17. 17.Use (a + b)(a − b) = a² − b² to find 21 × 19.
  18. 18.Find the value of x² + 2xy + y² when x = 14 and y = 10.
  19. 19.Find the value of x² − 2xy + y² when x = 5 and y = 2.
  20. 20.Use a² − b² = (a + b)(a − b) to find 64² − 61².
  21. 21.Use (a + b)² = a² + 2ab + b² to find 28².
  22. 22.Use a² − b² = (a + b)(a − b) to find 82² − 23².
  23. 23.Use a² − b² = (a + b)(a − b) to find 86² − 27².
  24. 24.Use a² − b² = (a + b)(a − b) to find 80² − 35².
  25. 25.If a + b = 13 and ab = 30, what is a² + b²?
  26. 26.Use (a + b)² = a² + 2ab + b² to find 88².
  27. 27.Find the value of x² − y² when x = 8 and y = 3.
  28. 28.Find the value of x² − y² when x = 13 and y = 7.
  29. 29.Use (a − b)² = a² − 2ab + b² to find 88².
  30. 30.Use (a − b)² = a² − 2ab + b² to find 59².
  31. 31.Use (a + b)² = a² + 2ab + b² to find 57².
  32. 32.Use (a − b)² = a² − 2ab + b² to find 61².
  33. 33.Use (a + b)² = a² + 2ab + b² to find 69².
  34. 34.Use (a − b)² = a² − 2ab + b² to find 75².
  35. 35.Use a² − b² = (a + b)(a − b) to find 66² − 31².
  36. 36.Use a² − b² = (a + b)(a − b) to find 64² − 38².
  37. 37.Use (a − b)² = a² − 2ab + b² to find 18².
  38. 38.Use (a − b)² = a² − 2ab + b² to find 52².
  39. 39.Find the value of x² − 2xy + y² when x = 13 and y = 9.
  40. 40.If a + b = 9 and ab = 20, what is a² + b²?

Answer key

  1. 1335
  2. 1296
  3. 81
  4. 625
  5. 896
  6. 3364
  7. 256
  8. 2304
  9. 1024
  10. 3481
  11. 49
  12. 5184
  13. 576
  14. 2601
  15. 4761
  16. 961
  17. 399
  18. 576
  19. 9
  20. 375
  21. 784
  22. 6195
  23. 6667
  24. 5175
  25. 109
  26. 7744
  27. 55
  28. 120
  29. 7744
  30. 3481
  31. 3249
  32. 3721
  33. 4761
  34. 5625
  35. 3395
  36. 2652
  37. 324
  38. 2704
  39. 16
  40. 41

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