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)(a − b) = a² − b² to find 59 × 41.
- 2.If a − b = 1 and ab = 2, what is a² + b²?
- 3.Use (a + b)² = a² + 2ab + b² to find 15².
- 4.Use a² − b² = (a + b)(a − b) to find 28² − 26².
- 5.Use (a + b)² = a² + 2ab + b² to find 69².
- 6.Use a² − b² = (a + b)(a − b) to find 83² − 55².
- 7.Use (a + b)² = a² + 2ab + b² to find 22².
- 8.Find the value of x² − 2xy + y² when x = 12 and y = 5.
- 9.If a − b = 3 and ab = 10, what is a² + b²?
- 10.Use (a + b)(a − b) = a² − b² to find 43 × 37.
- 11.If a + b = 5 and ab = 4, what is a² + b²?
- 12.If a − b = 1 and ab = 6, what is a² + b²?
- 13.If a + b = 5 and ab = 6, what is a² + b²?
- 14.If a + b = 12 and ab = 35, what is a² + b²?
- 15.Use (a + b)(a − b) = a² − b² to find 96 × 84.
- 16.Find the value of x² + 2xy + y² when x = 14 and y = 2.
- 17.Use (a + b)² = a² + 2ab + b² to find 58².
- 18.Find the value of x² − y² when x = 13 and y = 8.
- 19.Find the value of x² − y² when x = 13 and y = 4.
- 20.Use (a − b)² = a² − 2ab + b² to find 22².
- 21.If a − b = 3 and ab = 40, what is a² + b²?
- 22.Use (a + b)(a − b) = a² − b² to find 52 × 48.
- 23.Use a² − b² = (a + b)(a − b) to find 25² − 13².
- 24.Use (a + b)(a − b) = a² − b² to find 34 × 26.
- 25.Find the value of x² + 2xy + y² when x = 11 and y = 1.
- 26.Use (a − b)² = a² − 2ab + b² to find 15².
- 27.Use (a + b)² = a² + 2ab + b² to find 55².
- 28.Use a² − b² = (a + b)(a − b) to find 81² − 61².
- 29.Use (a + b)² = a² + 2ab + b² to find 33².
- 30.Use (a − b)² = a² − 2ab + b² to find 23².
- 31.Use a² − b² = (a + b)(a − b) to find 33² − 32².
- 32.Use (a − b)² = a² − 2ab + b² to find 67².
- 33.Use (a + b)² = a² + 2ab + b² to find 92².
- 34.Use a² − b² = (a + b)(a − b) to find 25² − 2².
- 35.Use (a + b)(a − b) = a² − b² to find 31 × 29.
- 36.Find the value of x² + 2xy + y² when x = 8 and y = 6.
- 37.Use (a − b)² = a² − 2ab + b² to find 42².
- 38.Use (a + b)(a − b) = a² − b² to find 24 × 16.
- 39.Use (a − b)² = a² − 2ab + b² to find 93².
- 40.Use (a + b)(a − b) = a² − b² to find 42 × 38.
Answer key
- 2419
- 5
- 225
- 108
- 4761
- 3864
- 484
- 49
- 29
- 1591
- 17
- 13
- 13
- 74
- 8064
- 256
- 3364
- 105
- 153
- 484
- 89
- 2496
- 456
- 884
- 144
- 225
- 3025
- 2840
- 1089
- 529
- 65
- 4489
- 8464
- 621
- 899
- 196
- 1764
- 384
- 8649
- 1596
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