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Class 8 Maths Worksheet: Algebraic Identities

Maths worksheets lesson 61: Algebraic identities · Set 986 · 40 sums
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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 = 2.
  2. 2.Use (a + b)(a − b) = a² − b² to find 29 × 11.
  3. 3.If a − b = 10 and ab = 11, what is a² + b²?
  4. 4.Use (a − b)² = a² − 2ab + b² to find 75².
  5. 5.Use (a − b)² = a² − 2ab + b² to find 87².
  6. 6.Use (a + b)² = a² + 2ab + b² to find 33².
  7. 7.If a − b = 1 and ab = 12, what is a² + b²?
  8. 8.If a − b = 5 and ab = 66, what is a² + b²?
  9. 9.Use (a + b)² = a² + 2ab + b² to find 14².
  10. 10.Find the value of x² − y² when x = 12 and y = 7.
  11. 11.Find the value of x² − 2xy + y² when x = 12 and y = 11.
  12. 12.Use (a + b)(a − b) = a² − b² to find 44 × 36.
  13. 13.Use a² − b² = (a + b)(a − b) to find 98² − 95².
  14. 14.Use a² − b² = (a + b)(a − b) to find 44² − 9².
  15. 15.Use (a + b)² = a² + 2ab + b² to find 48².
  16. 16.Find the value of x² − y² when x = 6 and y = 4.
  17. 17.Use (a + b)² = a² + 2ab + b² to find 69².
  18. 18.Find the value of x² + 2xy + y² when x = 10 and y = 3.
  19. 19.Use a² − b² = (a + b)(a − b) to find 94² − 75².
  20. 20.Use (a + b)(a − b) = a² − b² to find 107 × 93.
  21. 21.Use (a + b)(a − b) = a² − b² to find 78 × 62.
  22. 22.Use (a − b)² = a² − 2ab + b² to find 46².
  23. 23.If a − b = 1 and ab = 2, what is a² + b²?
  24. 24.Use a² − b² = (a + b)(a − b) to find 53² − 26².
  25. 25.Find the value of x² + 2xy + y² when x = 15 and y = 4.
  26. 26.Find the value of x² − 2xy + y² when x = 13 and y = 6.
  27. 27.Find the value of x² + 2xy + y² when x = 6 and y = 1.
  28. 28.Use (a + b)(a − b) = a² − b² to find 53 × 47.
  29. 29.Use (a + b)² = a² + 2ab + b² to find 13².
  30. 30.Use (a + b)(a − b) = a² − b² to find 34 × 26.
  31. 31.Find the value of x² − 2xy + y² when x = 3 and y = 2.
  32. 32.Use (a + b)(a − b) = a² − b² to find 67 × 53.
  33. 33.Use (a − b)² = a² − 2ab + b² to find 67².
  34. 34.Use (a − b)² = a² − 2ab + b² to find 72².
  35. 35.Find the value of x² − 2xy + y² when x = 12 and y = 10.
  36. 36.If a + b = 5 and ab = 6, what is a² + b²?
  37. 37.Find the value of x² − 2xy + y² when x = 13 and y = 7.
  38. 38.Use (a − b)² = a² − 2ab + b² to find 29².
  39. 39.Use (a + b)² = a² + 2ab + b² to find 54².
  40. 40.Use (a + b)² = a² + 2ab + b² to find 47².

Answer key

  1. 140
  2. 319
  3. 122
  4. 5625
  5. 7569
  6. 1089
  7. 25
  8. 157
  9. 196
  10. 95
  11. 1
  12. 1584
  13. 579
  14. 1855
  15. 2304
  16. 20
  17. 4761
  18. 169
  19. 3211
  20. 9951
  21. 4836
  22. 2116
  23. 5
  24. 2133
  25. 361
  26. 49
  27. 49
  28. 2491
  29. 169
  30. 884
  31. 1
  32. 3551
  33. 4489
  34. 5184
  35. 4
  36. 13
  37. 36
  38. 841
  39. 2916
  40. 2209

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