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.If a − b = 2 and ab = 35, what is a² + b²?
- 2.Use a² − b² = (a + b)(a − b) to find 34² − 13².
- 3.Use (a − b)² = a² − 2ab + b² to find 88².
- 4.Find the value of x² − y² when x = 15 and y = 7.
- 5.Use (a + b)² = a² + 2ab + b² to find 16².
- 6.Use a² − b² = (a + b)(a − b) to find 67² − 33².
- 7.Use (a + b)² = a² + 2ab + b² to find 92².
- 8.Use (a + b)² = a² + 2ab + b² to find 101².
- 9.Use (a − b)² = a² − 2ab + b² to find 45².
- 10.If a − b = 1 and ab = 6, what is a² + b²?
- 11.Use (a + b)(a − b) = a² − b² to find 104 × 96.
- 12.If a − b = 10 and ab = 24, what is a² + b²?
- 13.Use (a − b)² = a² − 2ab + b² to find 53².
- 14.Use (a + b)² = a² + 2ab + b² to find 105².
- 15.Use (a − b)² = a² − 2ab + b² to find 12².
- 16.Use a² − b² = (a + b)(a − b) to find 22² − 9².
- 17.Find the value of x² − y² when x = 4 and y = 1.
- 18.Use (a + b)² = a² + 2ab + b² to find 47².
- 19.Use (a + b)² = a² + 2ab + b² to find 28².
- 20.If a − b = 5 and ab = 36, what is a² + b²?
- 21.Use a² − b² = (a + b)(a − b) to find 49² − 18².
- 22.Find the value of x² + 2xy + y² when x = 5 and y = 3.
- 23.If a + b = 9 and ab = 20, what is a² + b²?
- 24.Use (a + b)(a − b) = a² − b² to find 53 × 47.
- 25.Use a² − b² = (a + b)(a − b) to find 96² − 40².
- 26.Use (a + b)² = a² + 2ab + b² to find 87².
- 27.Use (a + b)² = a² + 2ab + b² to find 86².
- 28.Use (a + b)² = a² + 2ab + b² to find 99².
- 29.Find the value of x² − y² when x = 3 and y = 2.
- 30.Use (a − b)² = a² − 2ab + b² to find 16².
- 31.Use (a + b)² = a² + 2ab + b² to find 75².
- 32.Use a² − b² = (a + b)(a − b) to find 96² − 79².
- 33.If a − b = 2 and ab = 3, what is a² + b²?
- 34.Use a² − b² = (a + b)(a − b) to find 50² − 36².
- 35.Use (a + b)² = a² + 2ab + b² to find 43².
- 36.Use (a + b)² = a² + 2ab + b² to find 69².
- 37.Use (a − b)² = a² − 2ab + b² to find 64².
- 38.If a − b = 8 and ab = 9, what is a² + b²?
- 39.Find the value of x² − 2xy + y² when x = 5 and y = 4.
- 40.Use (a + b)(a − b) = a² − b² to find 91 × 89.
Answer key
- 74
- 987
- 7744
- 176
- 256
- 3400
- 8464
- 10201
- 2025
- 13
- 9984
- 148
- 2809
- 11025
- 144
- 403
- 15
- 2209
- 784
- 97
- 2077
- 64
- 41
- 2491
- 7616
- 7569
- 7396
- 9801
- 5
- 256
- 5625
- 2975
- 10
- 1204
- 1849
- 4761
- 4096
- 82
- 1
- 8099
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