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.Use (a − b)² = a² − 2ab + b² to find 61².
- 2.Use (a + b)(a − b) = a² − b² to find 36 × 24.
- 3.Use (a + b)² = a² + 2ab + b² to find 86².
- 4.Use (a + b)² = a² + 2ab + b² to find 102².
- 5.Use (a + b)² = a² + 2ab + b² to find 92².
- 6.Use (a − b)² = a² − 2ab + b² to find 39².
- 7.Find the value of x² + 2xy + y² when x = 11 and y = 9.
- 8.Use a² − b² = (a + b)(a − b) to find 96² − 55².
- 9.Use (a + b)² = a² + 2ab + b² to find 54².
- 10.If a + b = 15 and ab = 36, what is a² + b²?
- 11.Use (a + b)(a − b) = a² − b² to find 44 × 36.
- 12.Find the value of x² + 2xy + y² when x = 11 and y = 1.
- 13.Find the value of x² + 2xy + y² when x = 9 and y = 6.
- 14.Use (a + b)(a − b) = a² − b² to find 109 × 91.
- 15.Use a² − b² = (a + b)(a − b) to find 20² − 17².
- 16.Use (a + b)² = a² + 2ab + b² to find 12².
- 17.Use (a + b)(a − b) = a² − b² to find 34 × 26.
- 18.Use (a + b)² = a² + 2ab + b² to find 22².
- 19.If a + b = 21 and ab = 108, what is a² + b²?
- 20.Find the value of x² + 2xy + y² when x = 3 and y = 1.
- 21.Use (a + b)(a − b) = a² − b² to find 65 × 55.
- 22.Use (a − b)² = a² − 2ab + b² to find 77².
- 23.Use (a − b)² = a² − 2ab + b² to find 14².
- 24.Find the value of x² − y² when x = 9 and y = 1.
- 25.If a − b = 6 and ab = 7, what is a² + b²?
- 26.If a − b = 3 and ab = 108, what is a² + b²?
- 27.Use (a + b)² = a² + 2ab + b² to find 82².
- 28.Use (a + b)² = a² + 2ab + b² to find 103².
- 29.Use (a − b)² = a² − 2ab + b² to find 88².
- 30.Use (a − b)² = a² − 2ab + b² to find 45².
- 31.Use (a + b)² = a² + 2ab + b² to find 85².
- 32.Use a² − b² = (a + b)(a − b) to find 29² − 5².
- 33.Use (a + b)(a − b) = a² − b² to find 77 × 63.
- 34.Find the value of x² + 2xy + y² when x = 14 and y = 3.
- 35.Use a² − b² = (a + b)(a − b) to find 95² − 39².
- 36.Use a² − b² = (a + b)(a − b) to find 25² − 15².
- 37.Find the value of x² − y² when x = 5 and y = 1.
- 38.If a − b = 1 and ab = 2, what is a² + b²?
- 39.Use a² − b² = (a + b)(a − b) to find 32² − 26².
- 40.Use (a + b)² = a² + 2ab + b² to find 78².
Answer key
- 3721
- 864
- 7396
- 10404
- 8464
- 1521
- 400
- 6191
- 2916
- 153
- 1584
- 144
- 225
- 9919
- 111
- 144
- 884
- 484
- 225
- 16
- 3575
- 5929
- 196
- 80
- 50
- 225
- 6724
- 10609
- 7744
- 2025
- 7225
- 816
- 4851
- 289
- 7504
- 400
- 24
- 5
- 348
- 6084
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