← Algebraic identities lesson New set →

Class 8 Maths Worksheet: Algebraic Identities

Maths worksheets lesson 61: Algebraic identities · Set 82 · 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 57².
  2. 2.Use (a − b)² = a² − 2ab + b² to find 43².
  3. 3.Use (a + b)(a − b) = a² − b² to find 92 × 88.
  4. 4.Use (a + b)(a − b) = a² − b² to find 53 × 47.
  5. 5.Use (a − b)² = a² − 2ab + b² to find 99².
  6. 6.Use (a + b)² = a² + 2ab + b² to find 56².
  7. 7.Use a² − b² = (a + b)(a − b) to find 37² − 31².
  8. 8.Find the value of x² − 2xy + y² when x = 15 and y = 1.
  9. 9.Use a² − b² = (a + b)(a − b) to find 84² − 72².
  10. 10.Use a² − b² = (a + b)(a − b) to find 94² − 81².
  11. 11.Use (a + b)² = a² + 2ab + b² to find 91².
  12. 12.Use a² − b² = (a + b)(a − b) to find 81² − 69².
  13. 13.Use (a − b)² = a² − 2ab + b² to find 33².
  14. 14.Use a² − b² = (a + b)(a − b) to find 31² − 6².
  15. 15.Use (a − b)² = a² − 2ab + b² to find 61².
  16. 16.Find the value of x² − y² when x = 5 and y = 3.
  17. 17.Use a² − b² = (a + b)(a − b) to find 56² − 44².
  18. 18.If a + b = 3 and ab = 2, what is a² + b²?
  19. 19.Use (a + b)² = a² + 2ab + b² to find 13².
  20. 20.Use (a + b)(a − b) = a² − b² to find 99 × 81.
  21. 21.If a − b = 2 and ab = 63, what is a² + b²?
  22. 22.Use a² − b² = (a + b)(a − b) to find 24² − 3².
  23. 23.Use (a − b)² = a² − 2ab + b² to find 89².
  24. 24.If a − b = 4 and ab = 5, what is a² + b²?
  25. 25.Use (a + b)(a − b) = a² − b² to find 93 × 87.
  26. 26.Find the value of x² + 2xy + y² when x = 11 and y = 6.
  27. 27.Use (a − b)² = a² − 2ab + b² to find 79².
  28. 28.Use (a + b)(a − b) = a² − b² to find 35 × 25.
  29. 29.Find the value of x² − 2xy + y² when x = 12 and y = 1.
  30. 30.Use a² − b² = (a + b)(a − b) to find 20² − 17².
  31. 31.Find the value of x² + 2xy + y² when x = 10 and y = 2.
  32. 32.Use (a + b)(a − b) = a² − b² to find 103 × 97.
  33. 33.Use (a + b)² = a² + 2ab + b² to find 28².
  34. 34.Use (a + b)² = a² + 2ab + b² to find 37².
  35. 35.Use (a − b)² = a² − 2ab + b² to find 96².
  36. 36.Use a² − b² = (a + b)(a − b) to find 29² − 2².
  37. 37.Use (a − b)² = a² − 2ab + b² to find 45².
  38. 38.Use (a + b)² = a² + 2ab + b² to find 95².
  39. 39.Use a² − b² = (a + b)(a − b) to find 75² − 59².
  40. 40.If a + b = 15 and ab = 56, what is a² + b²?

Answer key

  1. 3249
  2. 1849
  3. 8096
  4. 2491
  5. 9801
  6. 3136
  7. 408
  8. 196
  9. 1872
  10. 2275
  11. 8281
  12. 1800
  13. 1089
  14. 925
  15. 3721
  16. 16
  17. 1200
  18. 5
  19. 169
  20. 8019
  21. 130
  22. 567
  23. 7921
  24. 26
  25. 8091
  26. 289
  27. 6241
  28. 875
  29. 121
  30. 111
  31. 144
  32. 9991
  33. 784
  34. 1369
  35. 9216
  36. 837
  37. 2025
  38. 9025
  39. 2144
  40. 113

Free maths worksheets lessons, practice and worksheets at talentjr.in/maths-worksheets