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 73².
- 2.Use (a − b)² = a² − 2ab + b² to find 26².
- 3.Use (a − b)² = a² − 2ab + b² to find 36².
- 4.Use a² − b² = (a + b)(a − b) to find 63² − 14².
- 5.Use (a + b)² = a² + 2ab + b² to find 64².
- 6.Use (a − b)² = a² − 2ab + b² to find 58².
- 7.If a − b = 8 and ab = 20, what is a² + b²?
- 8.Use (a + b)² = a² + 2ab + b² to find 58².
- 9.If a + b = 16 and ab = 60, what is a² + b²?
- 10.Find the value of x² − y² when x = 5 and y = 1.
- 11.Use (a + b)² = a² + 2ab + b² to find 72².
- 12.If a − b = 8 and ab = 48, what is a² + b²?
- 13.Use (a − b)² = a² − 2ab + b² to find 59².
- 14.Use (a + b)² = a² + 2ab + b² to find 56².
- 15.Use (a + b)² = a² + 2ab + b² to find 43².
- 16.If a − b = 7 and ab = 44, what is a² + b²?
- 17.If a − b = 1 and ab = 6, what is a² + b²?
- 18.Find the value of x² − y² when x = 6 and y = 1.
- 19.If a + b = 14 and ab = 48, what is a² + b²?
- 20.Find the value of x² − 2xy + y² when x = 4 and y = 1.
- 21.If a − b = 1 and ab = 42, what is a² + b²?
- 22.Use (a + b)² = a² + 2ab + b² to find 33².
- 23.Use (a − b)² = a² − 2ab + b² to find 39².
- 24.Find the value of x² − y² when x = 8 and y = 6.
- 25.Use a² − b² = (a + b)(a − b) to find 90² − 73².
- 26.Use (a + b)² = a² + 2ab + b² to find 15².
- 27.If a + b = 14 and ab = 45, what is a² + b²?
- 28.Use (a + b)(a − b) = a² − b² to find 46 × 34.
- 29.Use (a + b)² = a² + 2ab + b² to find 55².
- 30.If a − b = 2 and ab = 63, what is a² + b²?
- 31.Use (a + b)(a − b) = a² − b² to find 75 × 65.
- 32.Use (a − b)² = a² − 2ab + b² to find 28².
- 33.Use a² − b² = (a + b)(a − b) to find 36² − 10².
- 34.Use a² − b² = (a + b)(a − b) to find 35² − 7².
- 35.Use (a − b)² = a² − 2ab + b² to find 94².
- 36.Use (a − b)² = a² − 2ab + b² to find 16².
- 37.Use (a + b)(a − b) = a² − b² to find 69 × 51.
- 38.Use (a − b)² = a² − 2ab + b² to find 93².
- 39.If a − b = 2 and ab = 3, what is a² + b²?
- 40.Find the value of x² + 2xy + y² when x = 14 and y = 7.
Answer key
- 5329
- 676
- 1296
- 3773
- 4096
- 3364
- 104
- 3364
- 136
- 24
- 5184
- 160
- 3481
- 3136
- 1849
- 137
- 13
- 35
- 100
- 9
- 85
- 1089
- 1521
- 28
- 2771
- 225
- 106
- 1564
- 3025
- 130
- 4875
- 784
- 1196
- 1176
- 8836
- 256
- 3519
- 8649
- 10
- 441
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