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Class 8 Maths Worksheet: Algebraic Identities

Maths worksheets lesson 61: Algebraic identities · Set 459 · 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 + 2xy + y² when x = 3 and y = 2.
  2. 2.Use (a + b)(a − b) = a² − b² to find 62 × 58.
  3. 3.If a + b = 7 and ab = 12, what is a² + b²?
  4. 4.Use (a + b)(a − b) = a² − b² to find 64 × 56.
  5. 5.If a + b = 12 and ab = 27, what is a² + b²?
  6. 6.If a − b = 3 and ab = 10, what is a² + b²?
  7. 7.Use a² − b² = (a + b)(a − b) to find 63² − 57².
  8. 8.Use (a + b)² = a² + 2ab + b² to find 52².
  9. 9.Use (a + b)² = a² + 2ab + b² to find 76².
  10. 10.Use (a − b)² = a² − 2ab + b² to find 72².
  11. 11.If a − b = 6 and ab = 7, what is a² + b²?
  12. 12.Use (a + b)² = a² + 2ab + b² to find 97².
  13. 13.Use (a − b)² = a² − 2ab + b² to find 29².
  14. 14.Use (a + b)² = a² + 2ab + b² to find 56².
  15. 15.Use (a − b)² = a² − 2ab + b² to find 53².
  16. 16.Find the value of x² − 2xy + y² when x = 12 and y = 7.
  17. 17.Use (a − b)² = a² − 2ab + b² to find 58².
  18. 18.If a − b = 9 and ab = 22, what is a² + b²?
  19. 19.Find the value of x² − y² when x = 12 and y = 10.
  20. 20.Use a² − b² = (a + b)(a − b) to find 25² − 19².
  21. 21.Use (a − b)² = a² − 2ab + b² to find 85².
  22. 22.Use (a + b)² = a² + 2ab + b² to find 85².
  23. 23.Use (a + b)² = a² + 2ab + b² to find 12².
  24. 24.Use (a − b)² = a² − 2ab + b² to find 37².
  25. 25.Use a² − b² = (a + b)(a − b) to find 20² − 1².
  26. 26.Use (a − b)² = a² − 2ab + b² to find 28².
  27. 27.Use (a − b)² = a² − 2ab + b² to find 69².
  28. 28.Use (a + b)(a − b) = a² − b² to find 108 × 92.
  29. 29.Use (a + b)(a − b) = a² − b² to find 22 × 18.
  30. 30.Use (a + b)(a − b) = a² − b² to find 73 × 67.
  31. 31.Find the value of x² + 2xy + y² when x = 10 and y = 3.
  32. 32.Use (a − b)² = a² − 2ab + b² to find 34².
  33. 33.Use (a − b)² = a² − 2ab + b² to find 76².
  34. 34.Find the value of x² − y² when x = 13 and y = 3.
  35. 35.Use (a − b)² = a² − 2ab + b² to find 17².
  36. 36.Use (a + b)² = a² + 2ab + b² to find 89².
  37. 37.Use (a + b)(a − b) = a² − b² to find 96 × 84.
  38. 38.Use (a + b)(a − b) = a² − b² to find 104 × 96.
  39. 39.Use a² − b² = (a + b)(a − b) to find 64² − 48².
  40. 40.Find the value of x² − 2xy + y² when x = 9 and y = 4.

Answer key

  1. 25
  2. 3596
  3. 25
  4. 3584
  5. 90
  6. 29
  7. 720
  8. 2704
  9. 5776
  10. 5184
  11. 50
  12. 9409
  13. 841
  14. 3136
  15. 2809
  16. 25
  17. 3364
  18. 125
  19. 44
  20. 264
  21. 7225
  22. 7225
  23. 144
  24. 1369
  25. 399
  26. 784
  27. 4761
  28. 9936
  29. 396
  30. 4891
  31. 169
  32. 1156
  33. 5776
  34. 160
  35. 289
  36. 7921
  37. 8064
  38. 9984
  39. 1792
  40. 25

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