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Class 8 Maths Worksheet: Algebraic Identities

Maths worksheets lesson 61: Algebraic identities · Set 348 · 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 = 12 and y = 4.
  2. 2.Find the value of x² − 2xy + y² when x = 3 and y = 1.
  3. 3.Use (a − b)² = a² − 2ab + b² to find 15².
  4. 4.Find the value of x² − 2xy + y² when x = 6 and y = 1.
  5. 5.Use a² − b² = (a + b)(a − b) to find 37² − 3².
  6. 6.Use (a − b)² = a² − 2ab + b² to find 65².
  7. 7.Use (a + b)(a − b) = a² − b² to find 21 × 19.
  8. 8.Use (a + b)(a − b) = a² − b² to find 91 × 89.
  9. 9.Use (a − b)² = a² − 2ab + b² to find 89².
  10. 10.Use (a − b)² = a² − 2ab + b² to find 64².
  11. 11.Use (a + b)² = a² + 2ab + b² to find 79².
  12. 12.Find the value of x² − y² when x = 4 and y = 1.
  13. 13.Use (a + b)² = a² + 2ab + b² to find 64².
  14. 14.Use (a + b)² = a² + 2ab + b² to find 73².
  15. 15.Use (a − b)² = a² − 2ab + b² to find 69².
  16. 16.Use a² − b² = (a + b)(a − b) to find 28² − 27².
  17. 17.Use a² − b² = (a + b)(a − b) to find 27² − 16².
  18. 18.Use (a − b)² = a² − 2ab + b² to find 21².
  19. 19.Use (a + b)² = a² + 2ab + b² to find 62².
  20. 20.Use (a + b)(a − b) = a² − b² to find 52 × 48.
  21. 21.Use (a + b)(a − b) = a² − b² to find 58 × 42.
  22. 22.Use a² − b² = (a + b)(a − b) to find 69² − 5².
  23. 23.Use (a + b)(a − b) = a² − b² to find 33 × 27.
  24. 24.If a + b = 5 and ab = 6, what is a² + b²?
  25. 25.Use (a + b)(a − b) = a² − b² to find 28 × 12.
  26. 26.Find the value of x² + 2xy + y² when x = 7 and y = 2.
  27. 27.Find the value of x² + 2xy + y² when x = 12 and y = 6.
  28. 28.Use (a + b)(a − b) = a² − b² to find 104 × 96.
  29. 29.Use (a + b)(a − b) = a² − b² to find 89 × 71.
  30. 30.Use (a + b)² = a² + 2ab + b² to find 52².
  31. 31.Use (a − b)² = a² − 2ab + b² to find 97².
  32. 32.If a + b = 6 and ab = 8, what is a² + b²?
  33. 33.Find the value of x² − 2xy + y² when x = 12 and y = 2.
  34. 34.Use (a + b)(a − b) = a² − b² to find 108 × 92.
  35. 35.Use (a − b)² = a² − 2ab + b² to find 57².
  36. 36.If a + b = 8 and ab = 12, what is a² + b²?
  37. 37.Use a² − b² = (a + b)(a − b) to find 98² − 14².
  38. 38.Use (a + b)(a − b) = a² − b² to find 37 × 23.
  39. 39.If a + b = 7 and ab = 12, what is a² + b²?
  40. 40.Use (a + b)(a − b) = a² − b² to find 68 × 52.

Answer key

  1. 64
  2. 4
  3. 225
  4. 25
  5. 1360
  6. 4225
  7. 399
  8. 8099
  9. 7921
  10. 4096
  11. 6241
  12. 15
  13. 4096
  14. 5329
  15. 4761
  16. 55
  17. 473
  18. 441
  19. 3844
  20. 2496
  21. 2436
  22. 4736
  23. 891
  24. 13
  25. 336
  26. 81
  27. 324
  28. 9984
  29. 6319
  30. 2704
  31. 9409
  32. 20
  33. 100
  34. 9936
  35. 3249
  36. 40
  37. 9408
  38. 851
  39. 25
  40. 3536

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