Class 8 Maths Worksheet: Algebraic Identities
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.
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- 1.Find the value of x² − 2xy + y² when x = 5 and y = 3.
- 2.Use a² − b² = (a + b)(a − b) to find 21² − 6².
- 3.If a + b = 11 and ab = 24, what is a² + b²?
- 4.Use (a + b)² = a² + 2ab + b² to find 83².
- 5.Find the value of x² + 2xy + y² when x = 6 and y = 3.
- 6.Use (a + b)(a − b) = a² − b² to find 33 × 27.
- 7.If a + b = 9 and ab = 18, what is a² + b²?
- 8.Use a² − b² = (a + b)(a − b) to find 30² − 4².
- 9.Use (a + b)² = a² + 2ab + b² to find 77².
- 10.Use (a + b)² = a² + 2ab + b² to find 13².
- 11.Use (a + b)² = a² + 2ab + b² to find 82².
- 12.Find the value of x² − 2xy + y² when x = 13 and y = 1.
- 13.Use (a + b)(a − b) = a² − b² to find 29 × 11.
- 14.Use (a + b)(a − b) = a² − b² to find 21 × 19.
- 15.Use a² − b² = (a + b)(a − b) to find 75² − 25².
- 16.Find the value of x² − y² when x = 13 and y = 7.
- 17.Use a² − b² = (a + b)(a − b) to find 86² − 57².
- 18.Use (a − b)² = a² − 2ab + b² to find 31².
- 19.If a + b = 5 and ab = 6, what is a² + b²?
- 20.Use (a + b)(a − b) = a² − b² to find 27 × 13.
- 21.Use (a + b)² = a² + 2ab + b² to find 76².
- 22.If a − b = 7 and ab = 30, what is a² + b²?
- 23.Find the value of x² + 2xy + y² when x = 8 and y = 6.
- 24.Use (a + b)² = a² + 2ab + b² to find 47².
- 25.Use a² − b² = (a + b)(a − b) to find 23² − 19².
- 26.Use a² − b² = (a + b)(a − b) to find 77² − 27².
- 27.Use a² − b² = (a + b)(a − b) to find 50² − 44².
- 28.Find the value of x² − y² when x = 13 and y = 6.
- 29.Use (a + b)² = a² + 2ab + b² to find 65².
- 30.Find the value of x² − y² when x = 6 and y = 3.
- 31.Use (a − b)² = a² − 2ab + b² to find 28².
- 32.Use (a − b)² = a² − 2ab + b² to find 94².
- 33.Use a² − b² = (a + b)(a − b) to find 97² − 41².
- 34.Use a² − b² = (a + b)(a − b) to find 63² − 58².
- 35.Use (a − b)² = a² − 2ab + b² to find 36².
- 36.Use a² − b² = (a + b)(a − b) to find 91² − 14².
- 37.Use (a − b)² = a² − 2ab + b² to find 19².
- 38.Use a² − b² = (a + b)(a − b) to find 34² − 27².
- 39.Use (a + b)(a − b) = a² − b² to find 59 × 41.
- 40.Use (a + b)(a − b) = a² − b² to find 31 × 29.
Answer key
- 4
- 405
- 73
- 6889
- 81
- 891
- 45
- 884
- 5929
- 169
- 6724
- 144
- 319
- 399
- 5000
- 120
- 4147
- 961
- 13
- 351
- 5776
- 109
- 196
- 2209
- 168
- 5200
- 564
- 133
- 4225
- 27
- 784
- 8836
- 7728
- 605
- 1296
- 8085
- 361
- 427
- 2419
- 899
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