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Class 8 Maths Worksheet: Algebraic Identities

Maths worksheets lesson 61: Algebraic identities · Set 832 · 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.Use (a + b)² = a² + 2ab + b² to find 71².
  2. 2.Find the value of x² − y² when x = 8 and y = 2.
  3. 3.If a − b = 1 and ab = 132, what is a² + b²?
  4. 4.Use a² − b² = (a + b)(a − b) to find 31² − 21².
  5. 5.If a + b = 3 and ab = 2, what is a² + b²?
  6. 6.Use (a + b)(a − b) = a² − b² to find 88 × 72.
  7. 7.Use (a + b)² = a² + 2ab + b² to find 23².
  8. 8.If a − b = 2 and ab = 8, what is a² + b²?
  9. 9.If a + b = 9 and ab = 14, what is a² + b²?
  10. 10.Use (a + b)² = a² + 2ab + b² to find 27².
  11. 11.Use (a + b)(a − b) = a² − b² to find 23 × 17.
  12. 12.Find the value of x² + 2xy + y² when x = 11 and y = 1.
  13. 13.Find the value of x² + 2xy + y² when x = 14 and y = 7.
  14. 14.Use (a + b)² = a² + 2ab + b² to find 25².
  15. 15.Find the value of x² − y² when x = 11 and y = 8.
  16. 16.If a + b = 13 and ab = 22, what is a² + b²?
  17. 17.If a + b = 5 and ab = 6, what is a² + b²?
  18. 18.If a + b = 13 and ab = 12, what is a² + b²?
  19. 19.Use (a − b)² = a² − 2ab + b² to find 95².
  20. 20.Use (a + b)(a − b) = a² − b² to find 41 × 39.
  21. 21.Find the value of x² − y² when x = 10 and y = 3.
  22. 22.If a + b = 12 and ab = 11, what is a² + b²?
  23. 23.Use (a + b)(a − b) = a² − b² to find 43 × 37.
  24. 24.Use (a + b)(a − b) = a² − b² to find 65 × 55.
  25. 25.Use (a + b)(a − b) = a² − b² to find 29 × 11.
  26. 26.Use a² − b² = (a + b)(a − b) to find 40² − 1².
  27. 27.Use (a + b)² = a² + 2ab + b² to find 34².
  28. 28.Find the value of x² − 2xy + y² when x = 11 and y = 6.
  29. 29.Use (a − b)² = a² − 2ab + b² to find 32².
  30. 30.Use (a + b)² = a² + 2ab + b² to find 55².
  31. 31.Find the value of x² − 2xy + y² when x = 6 and y = 5.
  32. 32.Use (a + b)² = a² + 2ab + b² to find 84².
  33. 33.Use (a + b)(a − b) = a² − b² to find 54 × 46.
  34. 34.Use a² − b² = (a + b)(a − b) to find 58² − 56².
  35. 35.Use (a − b)² = a² − 2ab + b² to find 87².
  36. 36.If a − b = 1 and ab = 2, what is a² + b²?
  37. 37.Use (a − b)² = a² − 2ab + b² to find 88².
  38. 38.Find the value of x² − 2xy + y² when x = 14 and y = 9.
  39. 39.Use (a − b)² = a² − 2ab + b² to find 84².
  40. 40.If a + b = 16 and ab = 60, what is a² + b²?

Answer key

  1. 5041
  2. 60
  3. 265
  4. 520
  5. 5
  6. 6336
  7. 529
  8. 20
  9. 53
  10. 729
  11. 391
  12. 144
  13. 441
  14. 625
  15. 57
  16. 125
  17. 13
  18. 145
  19. 9025
  20. 1599
  21. 91
  22. 122
  23. 1591
  24. 3575
  25. 319
  26. 1599
  27. 1156
  28. 25
  29. 1024
  30. 3025
  31. 1
  32. 7056
  33. 2484
  34. 228
  35. 7569
  36. 5
  37. 7744
  38. 25
  39. 7056
  40. 136

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