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.Find the value of x² − y² when x = 14 and y = 7.
- 2.Use a² − b² = (a + b)(a − b) to find 83² − 55².
- 3.Use (a + b)² = a² + 2ab + b² to find 23².
- 4.Find the value of x² − 2xy + y² when x = 13 and y = 2.
- 5.If a − b = 3 and ab = 54, what is a² + b²?
- 6.Find the value of x² + 2xy + y² when x = 11 and y = 6.
- 7.Use (a − b)² = a² − 2ab + b² to find 61².
- 8.Use (a − b)² = a² − 2ab + b² to find 33².
- 9.Use (a − b)² = a² − 2ab + b² to find 35².
- 10.If a + b = 10 and ab = 24, what is a² + b²?
- 11.Find the value of x² + 2xy + y² when x = 15 and y = 3.
- 12.Use (a − b)² = a² − 2ab + b² to find 36².
- 13.Use (a + b)(a − b) = a² − b² to find 31 × 29.
- 14.Use (a + b)(a − b) = a² − b² to find 107 × 93.
- 15.Find the value of x² + 2xy + y² when x = 4 and y = 1.
- 16.Use (a − b)² = a² − 2ab + b² to find 71².
- 17.Use (a − b)² = a² − 2ab + b² to find 87².
- 18.If a + b = 7 and ab = 6, what is a² + b²?
- 19.If a + b = 3 and ab = 2, what is a² + b²?
- 20.If a − b = 2 and ab = 80, what is a² + b²?
- 21.Use (a + b)(a − b) = a² − b² to find 87 × 73.
- 22.Use (a + b)² = a² + 2ab + b² to find 102².
- 23.Use (a + b)(a − b) = a² − b² to find 83 × 77.
- 24.Use (a − b)² = a² − 2ab + b² to find 68².
- 25.Use (a − b)² = a² − 2ab + b² to find 31².
- 26.Use (a − b)² = a² − 2ab + b² to find 69².
- 27.Use (a + b)² = a² + 2ab + b² to find 101².
- 28.Find the value of x² − y² when x = 14 and y = 13.
- 29.Use a² − b² = (a + b)(a − b) to find 60² − 27².
- 30.Use (a − b)² = a² − 2ab + b² to find 67².
- 31.Use (a − b)² = a² − 2ab + b² to find 46².
- 32.If a − b = 4 and ab = 12, what is a² + b²?
- 33.Use (a + b)² = a² + 2ab + b² to find 82².
- 34.If a + b = 5 and ab = 4, what is a² + b²?
- 35.Find the value of x² − y² when x = 14 and y = 4.
- 36.Use (a + b)² = a² + 2ab + b² to find 13².
- 37.Find the value of x² + 2xy + y² when x = 7 and y = 1.
- 38.If a + b = 4 and ab = 3, what is a² + b²?
- 39.Use a² − b² = (a + b)(a − b) to find 69² − 51².
- 40.Use (a + b)² = a² + 2ab + b² to find 104².
Answer key
- 147
- 3864
- 529
- 121
- 117
- 289
- 3721
- 1089
- 1225
- 52
- 324
- 1296
- 899
- 9951
- 25
- 5041
- 7569
- 37
- 5
- 164
- 6351
- 10404
- 6391
- 4624
- 961
- 4761
- 10201
- 27
- 2871
- 4489
- 2116
- 40
- 6724
- 17
- 180
- 169
- 64
- 10
- 2160
- 10816
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