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 a² − b² = (a + b)(a − b) to find 39² − 35².
- 2.Use (a + b)² = a² + 2ab + b² to find 75².
- 3.Find the value of x² − 2xy + y² when x = 14 and y = 2.
- 4.Use a² − b² = (a + b)(a − b) to find 26² − 18².
- 5.Use (a + b)² = a² + 2ab + b² to find 33².
- 6.Use (a − b)² = a² − 2ab + b² to find 12².
- 7.Use (a + b)(a − b) = a² − b² to find 105 × 95.
- 8.Use a² − b² = (a + b)(a − b) to find 63² − 11².
- 9.Use (a + b)(a − b) = a² − b² to find 37 × 23.
- 10.Use (a + b)² = a² + 2ab + b² to find 48².
- 11.Use (a + b)(a − b) = a² − b² to find 92 × 88.
- 12.Use (a + b)² = a² + 2ab + b² to find 85².
- 13.If a + b = 6 and ab = 8, what is a² + b²?
- 14.Use (a − b)² = a² − 2ab + b² to find 17².
- 15.Use (a + b)(a − b) = a² − b² to find 76 × 64.
- 16.If a + b = 5 and ab = 4, what is a² + b²?
- 17.Use a² − b² = (a + b)(a − b) to find 32² − 25².
- 18.Find the value of x² + 2xy + y² when x = 4 and y = 3.
- 19.Find the value of x² + 2xy + y² when x = 9 and y = 2.
- 20.Use (a + b)² = a² + 2ab + b² to find 97².
- 21.If a − b = 6 and ab = 16, what is a² + b²?
- 22.Use (a + b)² = a² + 2ab + b² to find 86².
- 23.Use (a + b)² = a² + 2ab + b² to find 32².
- 24.Use a² − b² = (a + b)(a − b) to find 36² − 5².
- 25.If a − b = 2 and ab = 3, what is a² + b²?
- 26.Use (a − b)² = a² − 2ab + b² to find 81².
- 27.Use a² − b² = (a + b)(a − b) to find 36² − 18².
- 28.Use (a + b)(a − b) = a² − b² to find 72 × 68.
- 29.Use (a + b)(a − b) = a² − b² to find 41 × 39.
- 30.Find the value of x² − 2xy + y² when x = 3 and y = 2.
- 31.Find the value of x² − 2xy + y² when x = 13 and y = 2.
- 32.Use (a + b)² = a² + 2ab + b² to find 105².
- 33.Use (a + b)² = a² + 2ab + b² to find 84².
- 34.Use (a + b)² = a² + 2ab + b² to find 18².
- 35.Use a² − b² = (a + b)(a − b) to find 74² − 19².
- 36.Use a² − b² = (a + b)(a − b) to find 53² − 3².
- 37.Use (a − b)² = a² − 2ab + b² to find 67².
- 38.Use (a + b)² = a² + 2ab + b² to find 71².
- 39.Use (a + b)² = a² + 2ab + b² to find 93².
- 40.Use (a − b)² = a² − 2ab + b² to find 31².
Answer key
- 296
- 5625
- 144
- 352
- 1089
- 144
- 9975
- 3848
- 851
- 2304
- 8096
- 7225
- 20
- 289
- 4864
- 17
- 399
- 49
- 121
- 9409
- 68
- 7396
- 1024
- 1271
- 10
- 6561
- 972
- 4896
- 1599
- 1
- 121
- 11025
- 7056
- 324
- 5115
- 2800
- 4489
- 5041
- 8649
- 961
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