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 53².
- 2.Use a² − b² = (a + b)(a − b) to find 39² − 28².
- 3.Use (a + b)² = a² + 2ab + b² to find 52².
- 4.Find the value of x² − 2xy + y² when x = 11 and y = 9.
- 5.Use (a + b)(a − b) = a² − b² to find 105 × 95.
- 6.Use (a + b)² = a² + 2ab + b² to find 42².
- 7.Use (a + b)(a − b) = a² − b² to find 55 × 45.
- 8.Use (a + b)(a − b) = a² − b² to find 28 × 12.
- 9.Use (a + b)² = a² + 2ab + b² to find 107².
- 10.Find the value of x² + 2xy + y² when x = 8 and y = 2.
- 11.Use (a + b)(a − b) = a² − b² to find 24 × 16.
- 12.Use (a + b)² = a² + 2ab + b² to find 13².
- 13.If a − b = 7 and ab = 30, what is a² + b²?
- 14.Use (a − b)² = a² − 2ab + b² to find 52².
- 15.Use a² − b² = (a + b)(a − b) to find 81² − 31².
- 16.Find the value of x² + 2xy + y² when x = 15 and y = 12.
- 17.Use a² − b² = (a + b)(a − b) to find 81² − 46².
- 18.Use (a − b)² = a² − 2ab + b² to find 34².
- 19.If a + b = 4 and ab = 3, what is a² + b²?
- 20.If a + b = 12 and ab = 11, what is a² + b²?
- 21.Find the value of x² − 2xy + y² when x = 13 and y = 8.
- 22.Use (a − b)² = a² − 2ab + b² to find 56².
- 23.Use (a + b)(a − b) = a² − b² to find 71 × 69.
- 24.If a + b = 20 and ab = 99, what is a² + b²?
- 25.Use (a + b)(a − b) = a² − b² to find 31 × 29.
- 26.Find the value of x² − y² when x = 13 and y = 8.
- 27.Find the value of x² + 2xy + y² when x = 9 and y = 7.
- 28.Use (a + b)² = a² + 2ab + b² to find 75².
- 29.Use (a − b)² = a² − 2ab + b² to find 76².
- 30.Use (a − b)² = a² − 2ab + b² to find 68².
- 31.Use a² − b² = (a + b)(a − b) to find 50² − 26².
- 32.Use (a + b)² = a² + 2ab + b² to find 78².
- 33.Use (a + b)(a − b) = a² − b² to find 22 × 18.
- 34.If a + b = 6 and ab = 8, what is a² + b²?
- 35.Use a² − b² = (a + b)(a − b) to find 20² − 19².
- 36.Find the value of x² + 2xy + y² when x = 5 and y = 2.
- 37.Use a² − b² = (a + b)(a − b) to find 91² − 87².
- 38.Use (a + b)² = a² + 2ab + b² to find 73².
- 39.Use (a + b)(a − b) = a² − b² to find 61 × 59.
- 40.Find the value of x² − y² when x = 12 and y = 10.
Answer key
- 2809
- 737
- 2704
- 4
- 9975
- 1764
- 2475
- 336
- 11449
- 100
- 384
- 169
- 109
- 2704
- 5600
- 729
- 4445
- 1156
- 10
- 122
- 25
- 3136
- 4899
- 202
- 899
- 105
- 256
- 5625
- 5776
- 4624
- 1824
- 6084
- 396
- 20
- 39
- 49
- 712
- 5329
- 3599
- 44
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