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Class 8 Maths Worksheet: Algebraic Identities

Maths worksheets lesson 61: Algebraic identities · Set 663 · 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 = 4 and y = 2.
  2. 2.Use (a − b)² = a² − 2ab + b² to find 35².
  3. 3.Use (a + b)² = a² + 2ab + b² to find 54².
  4. 4.Use (a + b)² = a² + 2ab + b² to find 36².
  5. 5.Use (a + b)² = a² + 2ab + b² to find 34².
  6. 6.If a + b = 10 and ab = 9, what is a² + b²?
  7. 7.Use (a + b)² = a² + 2ab + b² to find 27².
  8. 8.Use (a + b)² = a² + 2ab + b² to find 33².
  9. 9.Use (a + b)(a − b) = a² − b² to find 53 × 47.
  10. 10.Find the value of x² − 2xy + y² when x = 13 and y = 4.
  11. 11.If a − b = 4 and ab = 32, what is a² + b²?
  12. 12.Use (a − b)² = a² − 2ab + b² to find 24².
  13. 13.If a − b = 5 and ab = 36, what is a² + b²?
  14. 14.Use a² − b² = (a + b)(a − b) to find 37² − 35².
  15. 15.Use (a − b)² = a² − 2ab + b² to find 33².
  16. 16.Find the value of x² − 2xy + y² when x = 5 and y = 2.
  17. 17.Use (a + b)² = a² + 2ab + b² to find 94².
  18. 18.Use a² − b² = (a + b)(a − b) to find 84² − 27².
  19. 19.Use (a + b)² = a² + 2ab + b² to find 18².
  20. 20.Use a² − b² = (a + b)(a − b) to find 72² − 1².
  21. 21.Use (a + b)(a − b) = a² − b² to find 93 × 87.
  22. 22.Find the value of x² − 2xy + y² when x = 3 and y = 1.
  23. 23.Use a² − b² = (a + b)(a − b) to find 99² − 4².
  24. 24.Use (a + b)² = a² + 2ab + b² to find 65².
  25. 25.Use (a + b)(a − b) = a² − b² to find 76 × 64.
  26. 26.Use a² − b² = (a + b)(a − b) to find 73² − 3².
  27. 27.Find the value of x² − y² when x = 9 and y = 2.
  28. 28.Use (a + b)² = a² + 2ab + b² to find 17².
  29. 29.Use (a + b)(a − b) = a² − b² to find 52 × 48.
  30. 30.Use (a + b)(a − b) = a² − b² to find 62 × 58.
  31. 31.If a − b = 2 and ab = 3, what is a² + b²?
  32. 32.Use (a + b)² = a² + 2ab + b² to find 15².
  33. 33.If a − b = 5 and ab = 24, what is a² + b²?
  34. 34.If a + b = 16 and ab = 55, what is a² + b²?
  35. 35.Find the value of x² + 2xy + y² when x = 10 and y = 5.
  36. 36.Use a² − b² = (a + b)(a − b) to find 90² − 72².
  37. 37.Use (a − b)² = a² − 2ab + b² to find 74².
  38. 38.Use (a + b)(a − b) = a² − b² to find 42 × 38.
  39. 39.Use (a + b)² = a² + 2ab + b² to find 63².
  40. 40.Use (a − b)² = a² − 2ab + b² to find 34².

Answer key

  1. 36
  2. 1225
  3. 2916
  4. 1296
  5. 1156
  6. 82
  7. 729
  8. 1089
  9. 2491
  10. 81
  11. 80
  12. 576
  13. 97
  14. 144
  15. 1089
  16. 9
  17. 8836
  18. 6327
  19. 324
  20. 5183
  21. 8091
  22. 4
  23. 9785
  24. 4225
  25. 4864
  26. 5320
  27. 77
  28. 289
  29. 2496
  30. 3596
  31. 10
  32. 225
  33. 73
  34. 146
  35. 225
  36. 2916
  37. 5476
  38. 1596
  39. 3969
  40. 1156

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