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 27².
- 2.Use a² − b² = (a + b)(a − b) to find 97² − 88².
- 3.If a − b = 3 and ab = 10, what is a² + b²?
- 4.Use (a − b)² = a² − 2ab + b² to find 72².
- 5.Use a² − b² = (a + b)(a − b) to find 97² − 9².
- 6.Use a² − b² = (a + b)(a − b) to find 57² − 14².
- 7.Use a² − b² = (a + b)(a − b) to find 34² − 20².
- 8.Find the value of x² − y² when x = 14 and y = 2.
- 9.Use (a − b)² = a² − 2ab + b² to find 84².
- 10.Find the value of x² − 2xy + y² when x = 5 and y = 1.
- 11.Use (a − b)² = a² − 2ab + b² to find 12².
- 12.Use (a + b)² = a² + 2ab + b² to find 58².
- 13.Use (a − b)² = a² − 2ab + b² to find 53².
- 14.If a − b = 7 and ab = 18, what is a² + b²?
- 15.Find the value of x² + 2xy + y² when x = 11 and y = 1.
- 16.Use a² − b² = (a + b)(a − b) to find 33² − 15².
- 17.Find the value of x² − 2xy + y² when x = 9 and y = 2.
- 18.Use a² − b² = (a + b)(a − b) to find 48² − 17².
- 19.Use (a − b)² = a² − 2ab + b² to find 54².
- 20.Use (a − b)² = a² − 2ab + b² to find 18².
- 21.Find the value of x² − 2xy + y² when x = 15 and y = 1.
- 22.If a + b = 20 and ab = 96, what is a² + b²?
- 23.Use (a + b)(a − b) = a² − b² to find 71 × 69.
- 24.If a − b = 1 and ab = 2, what is a² + b²?
- 25.Use a² − b² = (a + b)(a − b) to find 73² − 9².
- 26.Use (a + b)² = a² + 2ab + b² to find 16².
- 27.Use (a + b)² = a² + 2ab + b² to find 106².
- 28.If a − b = 6 and ab = 16, what is a² + b²?
- 29.Use (a − b)² = a² − 2ab + b² to find 16².
- 30.Use a² − b² = (a + b)(a − b) to find 89² − 21².
- 31.Use (a − b)² = a² − 2ab + b² to find 56².
- 32.Find the value of x² − y² when x = 12 and y = 11.
- 33.Use (a − b)² = a² − 2ab + b² to find 88².
- 34.Use (a − b)² = a² − 2ab + b² to find 58².
- 35.If a − b = 9 and ab = 36, what is a² + b²?
- 36.Use (a − b)² = a² − 2ab + b² to find 38².
- 37.Use (a + b)² = a² + 2ab + b² to find 56².
- 38.Use a² − b² = (a + b)(a − b) to find 25² − 24².
- 39.Use a² − b² = (a + b)(a − b) to find 90² − 52².
- 40.Use a² − b² = (a + b)(a − b) to find 61² − 53².
Answer key
- 729
- 1665
- 29
- 5184
- 9328
- 3053
- 756
- 192
- 7056
- 16
- 144
- 3364
- 2809
- 85
- 144
- 864
- 49
- 2015
- 2916
- 324
- 196
- 208
- 4899
- 5
- 5248
- 256
- 11236
- 68
- 256
- 7480
- 3136
- 23
- 7744
- 3364
- 153
- 1444
- 3136
- 49
- 5396
- 912
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