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 104 × 96.
- 2.Use (a + b)(a − b) = a² − b² to find 79 × 61.
- 3.Use (a + b)(a − b) = a² − b² to find 27 × 13.
- 4.Use (a + b)² = a² + 2ab + b² to find 26².
- 5.Use a² − b² = (a + b)(a − b) to find 85² − 25².
- 6.Use a² − b² = (a + b)(a − b) to find 61² − 11².
- 7.If a + b = 7 and ab = 12, what is a² + b²?
- 8.Use (a − b)² = a² − 2ab + b² to find 28².
- 9.If a + b = 15 and ab = 56, what is a² + b²?
- 10.If a − b = 2 and ab = 24, what is a² + b²?
- 11.Use (a − b)² = a² − 2ab + b² to find 59².
- 12.Use (a + b)² = a² + 2ab + b² to find 13².
- 13.Use a² − b² = (a + b)(a − b) to find 49² − 32².
- 14.Find the value of x² − 2xy + y² when x = 13 and y = 12.
- 15.If a + b = 13 and ab = 36, what is a² + b²?
- 16.Use (a − b)² = a² − 2ab + b² to find 32².
- 17.Use a² − b² = (a + b)(a − b) to find 73² − 44².
- 18.Find the value of x² − y² when x = 12 and y = 11.
- 19.Use (a − b)² = a² − 2ab + b² to find 75².
- 20.Use (a + b)(a − b) = a² − b² to find 21 × 19.
- 21.Use (a + b)² = a² + 2ab + b² to find 67².
- 22.Find the value of x² − 2xy + y² when x = 12 and y = 4.
- 23.Find the value of x² − 2xy + y² when x = 4 and y = 1.
- 24.Find the value of x² − 2xy + y² when x = 5 and y = 3.
- 25.Use (a + b)(a − b) = a² − b² to find 38 × 22.
- 26.If a + b = 11 and ab = 28, what is a² + b²?
- 27.Find the value of x² + 2xy + y² when x = 11 and y = 1.
- 28.Use (a − b)² = a² − 2ab + b² to find 85².
- 29.If a + b = 6 and ab = 8, what is a² + b²?
- 30.If a − b = 7 and ab = 30, what is a² + b²?
- 31.Use (a + b)² = a² + 2ab + b² to find 92².
- 32.Use (a + b)(a − b) = a² − b² to find 83 × 77.
- 33.Use (a + b)(a − b) = a² − b² to find 48 × 32.
- 34.Find the value of x² − y² when x = 4 and y = 2.
- 35.Use a² − b² = (a + b)(a − b) to find 99² − 55².
- 36.Use (a − b)² = a² − 2ab + b² to find 63².
- 37.Use (a − b)² = a² − 2ab + b² to find 48².
- 38.Find the value of x² + 2xy + y² when x = 14 and y = 6.
- 39.If a − b = 1 and ab = 6, what is a² + b²?
- 40.Find the value of x² − 2xy + y² when x = 12 and y = 11.
Answer key
- 9984
- 4819
- 351
- 676
- 6600
- 3600
- 25
- 784
- 113
- 52
- 3481
- 169
- 1377
- 1
- 97
- 1024
- 3393
- 23
- 5625
- 399
- 4489
- 64
- 9
- 4
- 836
- 65
- 144
- 7225
- 20
- 109
- 8464
- 6391
- 1536
- 12
- 6776
- 3969
- 2304
- 400
- 13
- 1
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