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Class 8 Maths Worksheet: Algebraic Identities

Maths worksheets lesson 61: Algebraic identities · Set 953 · 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.If a + b = 6 and ab = 8, what is a² + b²?
  2. 2.Use a² − b² = (a + b)(a − b) to find 44² − 29².
  3. 3.Use a² − b² = (a + b)(a − b) to find 81² − 42².
  4. 4.Find the value of x² + 2xy + y² when x = 15 and y = 7.
  5. 5.Use (a + b)² = a² + 2ab + b² to find 26².
  6. 6.Use a² − b² = (a + b)(a − b) to find 39² − 31².
  7. 7.Use (a − b)² = a² − 2ab + b² to find 11².
  8. 8.Use (a + b)² = a² + 2ab + b² to find 101².
  9. 9.If a + b = 6 and ab = 5, what is a² + b²?
  10. 10.Use (a + b)² = a² + 2ab + b² to find 61².
  11. 11.Use (a − b)² = a² − 2ab + b² to find 29².
  12. 12.Use (a + b)² = a² + 2ab + b² to find 13².
  13. 13.Use (a + b)(a − b) = a² − b² to find 67 × 53.
  14. 14.Find the value of x² − 2xy + y² when x = 13 and y = 6.
  15. 15.Use (a + b)(a − b) = a² − b² to find 34 × 26.
  16. 16.If a + b = 11 and ab = 28, what is a² + b²?
  17. 17.Use (a − b)² = a² − 2ab + b² to find 77².
  18. 18.Use (a + b)(a − b) = a² − b² to find 85 × 75.
  19. 19.Use (a − b)² = a² − 2ab + b² to find 98².
  20. 20.If a + b = 5 and ab = 4, what is a² + b²?
  21. 21.Use (a − b)² = a² − 2ab + b² to find 17².
  22. 22.Use (a − b)² = a² − 2ab + b² to find 79².
  23. 23.Find the value of x² − y² when x = 6 and y = 5.
  24. 24.Use (a + b)² = a² + 2ab + b² to find 42².
  25. 25.Use (a + b)(a − b) = a² − b² to find 93 × 87.
  26. 26.Use (a − b)² = a² − 2ab + b² to find 28².
  27. 27.Find the value of x² − 2xy + y² when x = 4 and y = 3.
  28. 28.If a + b = 10 and ab = 9, what is a² + b²?
  29. 29.Use (a + b)(a − b) = a² − b² to find 72 × 68.
  30. 30.Use (a + b)² = a² + 2ab + b² to find 49².
  31. 31.Use (a − b)² = a² − 2ab + b² to find 36².
  32. 32.Use (a + b)(a − b) = a² − b² to find 62 × 58.
  33. 33.If a + b = 19 and ab = 84, what is a² + b²?
  34. 34.Use a² − b² = (a + b)(a − b) to find 59² − 10².
  35. 35.If a + b = 8 and ab = 7, what is a² + b²?
  36. 36.Use (a + b)² = a² + 2ab + b² to find 12².
  37. 37.Use (a + b)(a − b) = a² − b² to find 101 × 99.
  38. 38.Find the value of x² + 2xy + y² when x = 10 and y = 6.
  39. 39.Use (a + b)² = a² + 2ab + b² to find 54².
  40. 40.Use (a + b)² = a² + 2ab + b² to find 32².

Answer key

  1. 20
  2. 1095
  3. 4797
  4. 484
  5. 676
  6. 560
  7. 121
  8. 10201
  9. 26
  10. 3721
  11. 841
  12. 169
  13. 3551
  14. 49
  15. 884
  16. 65
  17. 5929
  18. 6375
  19. 9604
  20. 17
  21. 289
  22. 6241
  23. 11
  24. 1764
  25. 8091
  26. 784
  27. 1
  28. 82
  29. 4896
  30. 2401
  31. 1296
  32. 3596
  33. 193
  34. 3381
  35. 50
  36. 144
  37. 9999
  38. 256
  39. 2916
  40. 1024

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