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Class 8 Maths Worksheet: Algebraic Identities

Maths worksheets lesson 61: Algebraic identities · Set 838 · 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 = 15 and y = 14.
  2. 2.Use (a + b)² = a² + 2ab + b² to find 32².
  3. 3.Find the value of x² − 2xy + y² when x = 9 and y = 5.
  4. 4.Use (a + b)(a − b) = a² − b² to find 56 × 44.
  5. 5.Use a² − b² = (a + b)(a − b) to find 47² − 19².
  6. 6.Find the value of x² − 2xy + y² when x = 14 and y = 9.
  7. 7.If a − b = 2 and ab = 8, what is a² + b²?
  8. 8.Use (a + b)² = a² + 2ab + b² to find 35².
  9. 9.Use a² − b² = (a + b)(a − b) to find 39² − 7².
  10. 10.Use (a + b)(a − b) = a² − b² to find 76 × 64.
  11. 11.Use (a + b)² = a² + 2ab + b² to find 38².
  12. 12.Use (a + b)(a − b) = a² − b² to find 43 × 37.
  13. 13.Use a² − b² = (a + b)(a − b) to find 93² − 2².
  14. 14.Use (a + b)² = a² + 2ab + b² to find 95².
  15. 15.If a + b = 7 and ab = 12, what is a² + b²?
  16. 16.Use (a + b)² = a² + 2ab + b² to find 13².
  17. 17.Use a² − b² = (a + b)(a − b) to find 31² − 21².
  18. 18.Use (a + b)(a − b) = a² − b² to find 41 × 39.
  19. 19.Find the value of x² + 2xy + y² when x = 9 and y = 5.
  20. 20.Find the value of x² − y² when x = 3 and y = 1.
  21. 21.Use a² − b² = (a + b)(a − b) to find 94² − 54².
  22. 22.Find the value of x² − y² when x = 10 and y = 5.
  23. 23.Use (a − b)² = a² − 2ab + b² to find 72².
  24. 24.If a + b = 14 and ab = 45, what is a² + b²?
  25. 25.Find the value of x² + 2xy + y² when x = 9 and y = 4.
  26. 26.Use (a + b)(a − b) = a² − b² to find 83 × 77.
  27. 27.Use (a + b)² = a² + 2ab + b² to find 33².
  28. 28.Use (a + b)² = a² + 2ab + b² to find 36².
  29. 29.Use (a + b)² = a² + 2ab + b² to find 19².
  30. 30.If a − b = 1 and ab = 2, what is a² + b²?
  31. 31.Use (a − b)² = a² − 2ab + b² to find 89².
  32. 32.Use (a + b)² = a² + 2ab + b² to find 103².
  33. 33.Use (a + b)² = a² + 2ab + b² to find 12².
  34. 34.Use (a + b)(a − b) = a² − b² to find 38 × 22.
  35. 35.If a + b = 17 and ab = 60, what is a² + b²?
  36. 36.Use (a − b)² = a² − 2ab + b² to find 91².
  37. 37.Use (a + b)² = a² + 2ab + b² to find 34².
  38. 38.Use (a + b)² = a² + 2ab + b² to find 49².
  39. 39.Use (a − b)² = a² − 2ab + b² to find 68².
  40. 40.Use (a − b)² = a² − 2ab + b² to find 16².

Answer key

  1. 1
  2. 1024
  3. 16
  4. 2464
  5. 1848
  6. 25
  7. 20
  8. 1225
  9. 1472
  10. 4864
  11. 1444
  12. 1591
  13. 8645
  14. 9025
  15. 25
  16. 169
  17. 520
  18. 1599
  19. 196
  20. 8
  21. 5920
  22. 75
  23. 5184
  24. 106
  25. 169
  26. 6391
  27. 1089
  28. 1296
  29. 361
  30. 5
  31. 7921
  32. 10609
  33. 144
  34. 836
  35. 169
  36. 8281
  37. 1156
  38. 2401
  39. 4624
  40. 256

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