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Class 8 Maths Worksheet: Algebraic Identities

Maths worksheets lesson 61: Algebraic identities · Set 318 · 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 + 2xy + y² when x = 10 and y = 3.
  2. 2.Use (a + b)² = a² + 2ab + b² to find 49².
  3. 3.Find the value of x² + 2xy + y² when x = 14 and y = 3.
  4. 4.If a − b = 5 and ab = 36, what is a² + b²?
  5. 5.Use (a + b)² = a² + 2ab + b² to find 27².
  6. 6.Find the value of x² + 2xy + y² when x = 3 and y = 2.
  7. 7.Use (a + b)(a − b) = a² − b² to find 32 × 28.
  8. 8.Use (a + b)² = a² + 2ab + b² to find 93².
  9. 9.Use (a − b)² = a² − 2ab + b² to find 12².
  10. 10.Use (a − b)² = a² − 2ab + b² to find 53².
  11. 11.Use (a + b)² = a² + 2ab + b² to find 74².
  12. 12.Use (a + b)(a − b) = a² − b² to find 98 × 82.
  13. 13.If a − b = 3 and ab = 88, what is a² + b²?
  14. 14.Find the value of x² + 2xy + y² when x = 5 and y = 1.
  15. 15.Use (a + b)(a − b) = a² − b² to find 45 × 35.
  16. 16.Use (a + b)² = a² + 2ab + b² to find 72².
  17. 17.Find the value of x² + 2xy + y² when x = 6 and y = 1.
  18. 18.Use (a + b)² = a² + 2ab + b² to find 101².
  19. 19.Use a² − b² = (a + b)(a − b) to find 23² − 22².
  20. 20.Use (a + b)(a − b) = a² − b² to find 82 × 78.
  21. 21.Find the value of x² − y² when x = 9 and y = 8.
  22. 22.Use a² − b² = (a + b)(a − b) to find 20² − 19².
  23. 23.Use (a + b)² = a² + 2ab + b² to find 98².
  24. 24.Use (a − b)² = a² − 2ab + b² to find 19².
  25. 25.Use (a + b)(a − b) = a² − b² to find 63 × 57.
  26. 26.Find the value of x² + 2xy + y² when x = 11 and y = 2.
  27. 27.Use (a + b)² = a² + 2ab + b² to find 35².
  28. 28.Use (a − b)² = a² − 2ab + b² to find 85².
  29. 29.If a + b = 6 and ab = 8, what is a² + b²?
  30. 30.Use a² − b² = (a + b)(a − b) to find 89² − 7².
  31. 31.Use (a + b)(a − b) = a² − b² to find 69 × 51.
  32. 32.Find the value of x² − y² when x = 15 and y = 13.
  33. 33.Use (a + b)² = a² + 2ab + b² to find 41².
  34. 34.Use (a + b)² = a² + 2ab + b² to find 68².
  35. 35.Use (a + b)(a − b) = a² − b² to find 57 × 43.
  36. 36.Use (a + b)(a − b) = a² − b² to find 21 × 19.
  37. 37.Use (a + b)² = a² + 2ab + b² to find 28².
  38. 38.Find the value of x² + 2xy + y² when x = 11 and y = 1.
  39. 39.Use a² − b² = (a + b)(a − b) to find 77² − 29².
  40. 40.Find the value of x² + 2xy + y² when x = 15 and y = 4.

Answer key

  1. 169
  2. 2401
  3. 289
  4. 97
  5. 729
  6. 25
  7. 896
  8. 8649
  9. 144
  10. 2809
  11. 5476
  12. 8036
  13. 185
  14. 36
  15. 1575
  16. 5184
  17. 49
  18. 10201
  19. 45
  20. 6396
  21. 17
  22. 39
  23. 9604
  24. 361
  25. 3591
  26. 169
  27. 1225
  28. 7225
  29. 20
  30. 7872
  31. 3519
  32. 56
  33. 1681
  34. 4624
  35. 2451
  36. 399
  37. 784
  38. 144
  39. 5088
  40. 361

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