← Algebraic identities lesson New set →

Class 8 Maths Worksheet: Algebraic Identities

Maths worksheets lesson 61: Algebraic identities · Set 865 · 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 a² − b² = (a + b)(a − b) to find 76² − 18².
  2. 2.Use (a − b)² = a² − 2ab + b² to find 41².
  3. 3.Find the value of x² + 2xy + y² when x = 14 and y = 12.
  4. 4.Use (a + b)² = a² + 2ab + b² to find 79².
  5. 5.Use a² − b² = (a + b)(a − b) to find 24² − 1².
  6. 6.Use (a + b)² = a² + 2ab + b² to find 19².
  7. 7.If a − b = 3 and ab = 18, what is a² + b²?
  8. 8.Use (a + b)² = a² + 2ab + b² to find 28².
  9. 9.Find the value of x² − 2xy + y² when x = 7 and y = 6.
  10. 10.If a + b = 7 and ab = 6, what is a² + b²?
  11. 11.If a + b = 3 and ab = 2, what is a² + b²?
  12. 12.Use (a − b)² = a² − 2ab + b² to find 46².
  13. 13.Use (a − b)² = a² − 2ab + b² to find 28².
  14. 14.Use (a + b)(a − b) = a² − b² to find 31 × 29.
  15. 15.Use (a + b)² = a² + 2ab + b² to find 31².
  16. 16.Use (a + b)² = a² + 2ab + b² to find 14².
  17. 17.Use (a − b)² = a² − 2ab + b² to find 29².
  18. 18.Find the value of x² − y² when x = 3 and y = 1.
  19. 19.Use (a − b)² = a² − 2ab + b² to find 78².
  20. 20.Use a² − b² = (a + b)(a − b) to find 86² − 60².
  21. 21.Use (a + b)(a − b) = a² − b² to find 53 × 47.
  22. 22.If a − b = 3 and ab = 10, what is a² + b²?
  23. 23.Use a² − b² = (a + b)(a − b) to find 78² − 53².
  24. 24.Find the value of x² + 2xy + y² when x = 11 and y = 9.
  25. 25.If a − b = 8 and ab = 20, what is a² + b²?
  26. 26.If a − b = 1 and ab = 12, what is a² + b²?
  27. 27.Use (a − b)² = a² − 2ab + b² to find 81².
  28. 28.Use (a − b)² = a² − 2ab + b² to find 89².
  29. 29.Find the value of x² − 2xy + y² when x = 13 and y = 11.
  30. 30.Use (a + b)² = a² + 2ab + b² to find 74².
  31. 31.Use (a + b)² = a² + 2ab + b² to find 16².
  32. 32.Find the value of x² + 2xy + y² when x = 8 and y = 6.
  33. 33.Use (a − b)² = a² − 2ab + b² to find 73².
  34. 34.Find the value of x² − y² when x = 3 and y = 2.
  35. 35.If a − b = 7 and ab = 18, what is a² + b²?
  36. 36.Find the value of x² − y² when x = 9 and y = 5.
  37. 37.If a − b = 1 and ab = 6, what is a² + b²?
  38. 38.Use (a + b)² = a² + 2ab + b² to find 25².
  39. 39.Use (a + b)² = a² + 2ab + b² to find 21².
  40. 40.Use (a − b)² = a² − 2ab + b² to find 85².

Answer key

  1. 5452
  2. 1681
  3. 676
  4. 6241
  5. 575
  6. 361
  7. 45
  8. 784
  9. 1
  10. 37
  11. 5
  12. 2116
  13. 784
  14. 899
  15. 961
  16. 196
  17. 841
  18. 8
  19. 6084
  20. 3796
  21. 2491
  22. 29
  23. 3275
  24. 400
  25. 104
  26. 25
  27. 6561
  28. 7921
  29. 4
  30. 5476
  31. 256
  32. 196
  33. 5329
  34. 5
  35. 85
  36. 56
  37. 13
  38. 625
  39. 441
  40. 7225

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