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Class 8 Maths Worksheet: Algebraic Identities

Maths worksheets lesson 61: Algebraic identities · Set 310 · 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.Find the value of x² + 2xy + y² when x = 14 and y = 3.
  3. 3.Use a² − b² = (a + b)(a − b) to find 63² − 38².
  4. 4.Use a² − b² = (a + b)(a − b) to find 51² − 48².
  5. 5.Use (a − b)² = a² − 2ab + b² to find 28².
  6. 6.Use (a − b)² = a² − 2ab + b² to find 43².
  7. 7.Use (a + b)² = a² + 2ab + b² to find 27².
  8. 8.Find the value of x² − y² when x = 6 and y = 2.
  9. 9.Use a² − b² = (a + b)(a − b) to find 79² − 41².
  10. 10.Use (a + b)² = a² + 2ab + b² to find 65².
  11. 11.Use (a − b)² = a² − 2ab + b² to find 77².
  12. 12.Use a² − b² = (a + b)(a − b) to find 66² − 56².
  13. 13.Use (a + b)² = a² + 2ab + b² to find 103².
  14. 14.Use (a + b)² = a² + 2ab + b² to find 47².
  15. 15.If a + b = 16 and ab = 55, what is a² + b²?
  16. 16.Use a² − b² = (a + b)(a − b) to find 65² − 15².
  17. 17.Find the value of x² − y² when x = 8 and y = 5.
  18. 18.Find the value of x² − 2xy + y² when x = 14 and y = 7.
  19. 19.If a − b = 1 and ab = 90, what is a² + b²?
  20. 20.Use (a − b)² = a² − 2ab + b² to find 32².
  21. 21.Use (a − b)² = a² − 2ab + b² to find 36².
  22. 22.Use (a + b)² = a² + 2ab + b² to find 49².
  23. 23.Use (a + b)² = a² + 2ab + b² to find 14².
  24. 24.Use (a + b)(a − b) = a² − b² to find 56 × 44.
  25. 25.Use (a + b)(a − b) = a² − b² to find 65 × 55.
  26. 26.Find the value of x² + 2xy + y² when x = 6 and y = 2.
  27. 27.Use (a + b)² = a² + 2ab + b² to find 79².
  28. 28.Use (a − b)² = a² − 2ab + b² to find 73².
  29. 29.Use (a + b)(a − b) = a² − b² to find 36 × 24.
  30. 30.Use (a + b)(a − b) = a² − b² to find 96 × 84.
  31. 31.Use (a + b)(a − b) = a² − b² to find 106 × 94.
  32. 32.Use (a + b)(a − b) = a² − b² to find 94 × 86.
  33. 33.Use (a + b)² = a² + 2ab + b² to find 37².
  34. 34.If a + b = 19 and ab = 90, what is a² + b²?
  35. 35.If a + b = 9 and ab = 14, what is a² + b²?
  36. 36.Use (a + b)(a − b) = a² − b² to find 29 × 11.
  37. 37.If a + b = 12 and ab = 27, what is a² + b²?
  38. 38.Use (a + b)² = a² + 2ab + b² to find 89².
  39. 39.Use (a − b)² = a² − 2ab + b² to find 46².
  40. 40.Find the value of x² − y² when x = 10 and y = 4.

Answer key

  1. 36
  2. 289
  3. 2525
  4. 297
  5. 784
  6. 1849
  7. 729
  8. 32
  9. 4560
  10. 4225
  11. 5929
  12. 1220
  13. 10609
  14. 2209
  15. 146
  16. 4000
  17. 39
  18. 49
  19. 181
  20. 1024
  21. 1296
  22. 2401
  23. 196
  24. 2464
  25. 3575
  26. 64
  27. 6241
  28. 5329
  29. 864
  30. 8064
  31. 9964
  32. 8084
  33. 1369
  34. 181
  35. 53
  36. 319
  37. 90
  38. 7921
  39. 2116
  40. 84

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