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Class 8 Maths Worksheet: Algebraic Identities

Maths worksheets lesson 61: Algebraic identities · Set 602 · 40 sums
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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 = 13 and y = 9.
  2. 2.Use (a + b)² = a² + 2ab + b² to find 35².
  3. 3.Use a² − b² = (a + b)(a − b) to find 70² − 52².
  4. 4.Use (a + b)² = a² + 2ab + b² to find 104².
  5. 5.If a + b = 16 and ab = 63, what is a² + b²?
  6. 6.Use (a + b)² = a² + 2ab + b² to find 73².
  7. 7.Use (a + b)² = a² + 2ab + b² to find 24².
  8. 8.If a − b = 10 and ab = 11, what is a² + b²?
  9. 9.Use a² − b² = (a + b)(a − b) to find 87² − 1².
  10. 10.If a − b = 1 and ab = 12, what is a² + b²?
  11. 11.Use a² − b² = (a + b)(a − b) to find 38² − 23².
  12. 12.Use (a + b)(a − b) = a² − b² to find 49 × 31.
  13. 13.Use (a + b)² = a² + 2ab + b² to find 45².
  14. 14.Use (a + b)(a − b) = a² − b² to find 53 × 47.
  15. 15.Use a² − b² = (a + b)(a − b) to find 83² − 62².
  16. 16.Use (a − b)² = a² − 2ab + b² to find 91².
  17. 17.Use (a + b)² = a² + 2ab + b² to find 21².
  18. 18.Use (a − b)² = a² − 2ab + b² to find 95².
  19. 19.Use (a − b)² = a² − 2ab + b² to find 77².
  20. 20.Use (a − b)² = a² − 2ab + b² to find 19².
  21. 21.Use a² − b² = (a + b)(a − b) to find 54² − 42².
  22. 22.Use (a + b)² = a² + 2ab + b² to find 34².
  23. 23.Use a² − b² = (a + b)(a − b) to find 41² − 20².
  24. 24.Use (a + b)² = a² + 2ab + b² to find 56².
  25. 25.Use a² − b² = (a + b)(a − b) to find 24² − 1².
  26. 26.Use (a + b)(a − b) = a² − b² to find 67 × 53.
  27. 27.If a + b = 16 and ab = 60, what is a² + b²?
  28. 28.Use (a + b)² = a² + 2ab + b² to find 64².
  29. 29.Use (a + b)(a − b) = a² − b² to find 62 × 58.
  30. 30.Find the value of x² + 2xy + y² when x = 13 and y = 4.
  31. 31.Use (a + b)(a − b) = a² − b² to find 101 × 99.
  32. 32.Use (a + b)² = a² + 2ab + b² to find 39².
  33. 33.Use a² − b² = (a + b)(a − b) to find 84² − 44².
  34. 34.If a − b = 4 and ab = 60, what is a² + b²?
  35. 35.Find the value of x² + 2xy + y² when x = 10 and y = 6.
  36. 36.Use a² − b² = (a + b)(a − b) to find 61² − 24².
  37. 37.Use (a − b)² = a² − 2ab + b² to find 98².
  38. 38.Find the value of x² + 2xy + y² when x = 4 and y = 3.
  39. 39.Use (a − b)² = a² − 2ab + b² to find 44².
  40. 40.Find the value of x² + 2xy + y² when x = 3 and y = 1.

Answer key

  1. 16
  2. 1225
  3. 2196
  4. 10816
  5. 130
  6. 5329
  7. 576
  8. 122
  9. 7568
  10. 25
  11. 915
  12. 1519
  13. 2025
  14. 2491
  15. 3045
  16. 8281
  17. 441
  18. 9025
  19. 5929
  20. 361
  21. 1152
  22. 1156
  23. 1281
  24. 3136
  25. 575
  26. 3551
  27. 136
  28. 4096
  29. 3596
  30. 289
  31. 9999
  32. 1521
  33. 5120
  34. 136
  35. 256
  36. 3145
  37. 9604
  38. 49
  39. 1936
  40. 16

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