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Class 8 Maths Worksheet: Algebraic Identities

Maths worksheets lesson 61: Algebraic identities · Set 955 · 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 = 11 and y = 2.
  2. 2.If a + b = 16 and ab = 55, what is a² + b²?
  3. 3.Use (a + b)(a − b) = a² − b² to find 32 × 28.
  4. 4.Use (a + b)(a − b) = a² − b² to find 44 × 36.
  5. 5.Use (a − b)² = a² − 2ab + b² to find 11².
  6. 6.If a − b = 10 and ab = 24, what is a² + b²?
  7. 7.If a + b = 14 and ab = 48, what is a² + b²?
  8. 8.If a − b = 6 and ab = 7, what is a² + b²?
  9. 9.Use (a + b)(a − b) = a² − b² to find 38 × 22.
  10. 10.Use (a + b)² = a² + 2ab + b² to find 103².
  11. 11.Use (a + b)² = a² + 2ab + b² to find 41².
  12. 12.Use (a + b)(a − b) = a² − b² to find 81 × 79.
  13. 13.If a + b = 7 and ab = 12, what is a² + b²?
  14. 14.If a − b = 1 and ab = 2, what is a² + b²?
  15. 15.Use (a − b)² = a² − 2ab + b² to find 68².
  16. 16.Use (a − b)² = a² − 2ab + b² to find 39².
  17. 17.Use (a − b)² = a² − 2ab + b² to find 49².
  18. 18.Find the value of x² + 2xy + y² when x = 4 and y = 1.
  19. 19.Find the value of x² − y² when x = 13 and y = 4.
  20. 20.Use (a − b)² = a² − 2ab + b² to find 75².
  21. 21.Find the value of x² − y² when x = 8 and y = 4.
  22. 22.If a + b = 3 and ab = 2, what is a² + b²?
  23. 23.Use (a − b)² = a² − 2ab + b² to find 47².
  24. 24.If a − b = 4 and ab = 5, what is a² + b²?
  25. 25.Use a² − b² = (a + b)(a − b) to find 56² − 48².
  26. 26.Find the value of x² − y² when x = 3 and y = 1.
  27. 27.Find the value of x² + 2xy + y² when x = 7 and y = 4.
  28. 28.Use (a + b)(a − b) = a² − b² to find 66 × 54.
  29. 29.If a − b = 1 and ab = 72, what is a² + b²?
  30. 30.If a + b = 14 and ab = 24, what is a² + b²?
  31. 31.Use (a + b)(a − b) = a² − b² to find 109 × 91.
  32. 32.Use a² − b² = (a + b)(a − b) to find 66² − 61².
  33. 33.Use (a + b)² = a² + 2ab + b² to find 29².
  34. 34.Use (a + b)² = a² + 2ab + b² to find 95².
  35. 35.Use (a + b)² = a² + 2ab + b² to find 32².
  36. 36.Use (a − b)² = a² − 2ab + b² to find 44².
  37. 37.Use (a + b)(a − b) = a² − b² to find 55 × 45.
  38. 38.Use (a − b)² = a² − 2ab + b² to find 24².
  39. 39.Use (a + b)(a − b) = a² − b² to find 102 × 98.
  40. 40.If a + b = 8 and ab = 12, what is a² + b²?

Answer key

  1. 169
  2. 146
  3. 896
  4. 1584
  5. 121
  6. 148
  7. 100
  8. 50
  9. 836
  10. 10609
  11. 1681
  12. 6399
  13. 25
  14. 5
  15. 4624
  16. 1521
  17. 2401
  18. 25
  19. 153
  20. 5625
  21. 48
  22. 5
  23. 2209
  24. 26
  25. 832
  26. 8
  27. 121
  28. 3564
  29. 145
  30. 148
  31. 9919
  32. 635
  33. 841
  34. 9025
  35. 1024
  36. 1936
  37. 2475
  38. 576
  39. 9996
  40. 40

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