← Algebraic identities lesson New set →

Class 8 Maths Worksheet: Algebraic Identities

Maths worksheets lesson 61: Algebraic identities · Set 528 · 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 − y² when x = 12 and y = 4.
  2. 2.Use (a + b)(a − b) = a² − b² to find 72 × 68.
  3. 3.Use (a − b)² = a² − 2ab + b² to find 91².
  4. 4.Use a² − b² = (a + b)(a − b) to find 49² − 10².
  5. 5.Use (a + b)² = a² + 2ab + b² to find 54².
  6. 6.Use a² − b² = (a + b)(a − b) to find 60² − 29².
  7. 7.Use (a + b)(a − b) = a² − b² to find 107 × 93.
  8. 8.Use (a + b)² = a² + 2ab + b² to find 25².
  9. 9.Find the value of x² + 2xy + y² when x = 8 and y = 4.
  10. 10.Find the value of x² − 2xy + y² when x = 4 and y = 3.
  11. 11.Use (a − b)² = a² − 2ab + b² to find 85².
  12. 12.Use (a − b)² = a² − 2ab + b² to find 89².
  13. 13.Find the value of x² + 2xy + y² when x = 3 and y = 2.
  14. 14.Use (a − b)² = a² − 2ab + b² to find 79².
  15. 15.If a + b = 10 and ab = 21, what is a² + b²?
  16. 16.Use (a + b)(a − b) = a² − b² to find 52 × 48.
  17. 17.If a + b = 9 and ab = 18, what is a² + b²?
  18. 18.Find the value of x² + 2xy + y² when x = 8 and y = 7.
  19. 19.Use (a + b)² = a² + 2ab + b² to find 29².
  20. 20.Use (a + b)² = a² + 2ab + b² to find 56².
  21. 21.Find the value of x² + 2xy + y² when x = 15 and y = 5.
  22. 22.Use (a + b)(a − b) = a² − b² to find 21 × 19.
  23. 23.Use a² − b² = (a + b)(a − b) to find 55² − 44².
  24. 24.If a + b = 9 and ab = 20, what is a² + b²?
  25. 25.Use (a + b)(a − b) = a² − b² to find 97 × 83.
  26. 26.Use a² − b² = (a + b)(a − b) to find 31² − 4².
  27. 27.Use a² − b² = (a + b)(a − b) to find 21² − 1².
  28. 28.Use (a + b)² = a² + 2ab + b² to find 48².
  29. 29.Use (a + b)² = a² + 2ab + b² to find 85².
  30. 30.Use (a + b)(a − b) = a² − b² to find 85 × 75.
  31. 31.Use (a − b)² = a² − 2ab + b² to find 99².
  32. 32.Use (a + b)(a − b) = a² − b² to find 63 × 57.
  33. 33.Use (a + b)(a − b) = a² − b² to find 93 × 87.
  34. 34.Find the value of x² + 2xy + y² when x = 14 and y = 5.
  35. 35.Find the value of x² − y² when x = 4 and y = 3.
  36. 36.Use (a − b)² = a² − 2ab + b² to find 59².
  37. 37.Use (a + b)² = a² + 2ab + b² to find 84².
  38. 38.Find the value of x² − y² when x = 5 and y = 3.
  39. 39.If a − b = 9 and ab = 22, what is a² + b²?
  40. 40.Use a² − b² = (a + b)(a − b) to find 31² − 23².

Answer key

  1. 128
  2. 4896
  3. 8281
  4. 2301
  5. 2916
  6. 2759
  7. 9951
  8. 625
  9. 144
  10. 1
  11. 7225
  12. 7921
  13. 25
  14. 6241
  15. 58
  16. 2496
  17. 45
  18. 225
  19. 841
  20. 3136
  21. 400
  22. 399
  23. 1089
  24. 41
  25. 8051
  26. 945
  27. 440
  28. 2304
  29. 7225
  30. 6375
  31. 9801
  32. 3591
  33. 8091
  34. 361
  35. 7
  36. 3481
  37. 7056
  38. 16
  39. 125
  40. 432

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