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 67².
- 2.Find the value of x² + 2xy + y² when x = 7 and y = 2.
- 3.Use (a + b)² = a² + 2ab + b² to find 42².
- 4.If a + b = 13 and ab = 30, what is a² + b²?
- 5.Use a² − b² = (a + b)(a − b) to find 54² − 47².
- 6.Use (a − b)² = a² − 2ab + b² to find 92².
- 7.Use (a + b)² = a² + 2ab + b² to find 93².
- 8.Use (a + b)² = a² + 2ab + b² to find 96².
- 9.Use (a − b)² = a² − 2ab + b² to find 55².
- 10.Use a² − b² = (a + b)(a − b) to find 30² − 9².
- 11.Use (a − b)² = a² − 2ab + b² to find 58².
- 12.Find the value of x² + 2xy + y² when x = 8 and y = 3.
- 13.Use (a + b)(a − b) = a² − b² to find 77 × 63.
- 14.Use (a + b)(a − b) = a² − b² to find 58 × 42.
- 15.Use (a − b)² = a² − 2ab + b² to find 77².
- 16.Find the value of x² − 2xy + y² when x = 3 and y = 2.
- 17.Use (a − b)² = a² − 2ab + b² to find 19².
- 18.Use (a − b)² = a² − 2ab + b² to find 65².
- 19.Use (a − b)² = a² − 2ab + b² to find 36².
- 20.Use (a + b)(a − b) = a² − b² to find 68 × 52.
- 21.Use (a + b)² = a² + 2ab + b² to find 85².
- 22.Use a² − b² = (a + b)(a − b) to find 92² − 28².
- 23.Use (a + b)² = a² + 2ab + b² to find 15².
- 24.Use (a + b)² = a² + 2ab + b² to find 22².
- 25.Use a² − b² = (a + b)(a − b) to find 98² − 35².
- 26.Find the value of x² − y² when x = 6 and y = 4.
- 27.Use (a + b)² = a² + 2ab + b² to find 72².
- 28.Use (a − b)² = a² − 2ab + b² to find 51².
- 29.Use (a + b)(a − b) = a² − b² to find 105 × 95.
- 30.Use (a + b)(a − b) = a² − b² to find 83 × 77.
- 31.Use (a + b)(a − b) = a² − b² to find 36 × 24.
- 32.Use (a + b)(a − b) = a² − b² to find 42 × 38.
- 33.If a − b = 1 and ab = 20, what is a² + b²?
- 34.Use (a + b)² = a² + 2ab + b² to find 47².
- 35.Use a² − b² = (a + b)(a − b) to find 81² − 2².
- 36.Find the value of x² − 2xy + y² when x = 3 and y = 1.
- 37.Use a² − b² = (a + b)(a − b) to find 43² − 2².
- 38.If a + b = 3 and ab = 2, what is a² + b²?
- 39.Use a² − b² = (a + b)(a − b) to find 54² − 17².
- 40.Use a² − b² = (a + b)(a − b) to find 34² − 2².
Answer key
- 4489
- 81
- 1764
- 109
- 707
- 8464
- 8649
- 9216
- 3025
- 819
- 3364
- 121
- 4851
- 2436
- 5929
- 1
- 361
- 4225
- 1296
- 3536
- 7225
- 7680
- 225
- 484
- 8379
- 20
- 5184
- 2601
- 9975
- 6391
- 864
- 1596
- 41
- 2209
- 6557
- 4
- 1845
- 5
- 2627
- 1152
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