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 19².
- 2.Use a² − b² = (a + b)(a − b) to find 55² − 47².
- 3.Use (a + b)² = a² + 2ab + b² to find 105².
- 4.Use (a + b)(a − b) = a² − b² to find 104 × 96.
- 5.Use a² − b² = (a + b)(a − b) to find 53² − 19².
- 6.Find the value of x² − 2xy + y² when x = 6 and y = 4.
- 7.If a + b = 11 and ab = 24, what is a² + b²?
- 8.Find the value of x² − 2xy + y² when x = 3 and y = 1.
- 9.Use (a + b)(a − b) = a² − b² to find 51 × 49.
- 10.Use (a − b)² = a² − 2ab + b² to find 53².
- 11.Find the value of x² + 2xy + y² when x = 3 and y = 1.
- 12.Use (a + b)² = a² + 2ab + b² to find 103².
- 13.Use (a + b)² = a² + 2ab + b² to find 31².
- 14.Find the value of x² − y² when x = 6 and y = 4.
- 15.Use (a − b)² = a² − 2ab + b² to find 21².
- 16.Use a² − b² = (a + b)(a − b) to find 31² − 26².
- 17.Use (a + b)² = a² + 2ab + b² to find 13².
- 18.If a + b = 10 and ab = 9, what is a² + b²?
- 19.Find the value of x² − y² when x = 3 and y = 2.
- 20.Find the value of x² − 2xy + y² when x = 5 and y = 4.
- 21.Find the value of x² + 2xy + y² when x = 11 and y = 6.
- 22.Use (a + b)(a − b) = a² − b² to find 55 × 45.
- 23.Use (a + b)² = a² + 2ab + b² to find 27².
- 24.If a + b = 15 and ab = 56, what is a² + b²?
- 25.Find the value of x² + 2xy + y² when x = 7 and y = 6.
- 26.Use (a + b)² = a² + 2ab + b² to find 42².
- 27.Use (a + b)² = a² + 2ab + b² to find 73².
- 28.Use (a − b)² = a² − 2ab + b² to find 59².
- 29.Use (a − b)² = a² − 2ab + b² to find 77².
- 30.Find the value of x² + 2xy + y² when x = 8 and y = 7.
- 31.Find the value of x² + 2xy + y² when x = 15 and y = 1.
- 32.Find the value of x² + 2xy + y² when x = 5 and y = 4.
- 33.Find the value of x² − 2xy + y² when x = 15 and y = 7.
- 34.Find the value of x² + 2xy + y² when x = 5 and y = 3.
- 35.Use (a − b)² = a² − 2ab + b² to find 11².
- 36.Use a² − b² = (a + b)(a − b) to find 98² − 14².
- 37.Find the value of x² − 2xy + y² when x = 12 and y = 11.
- 38.Use (a + b)(a − b) = a² − b² to find 52 × 48.
- 39.Use (a + b)² = a² + 2ab + b² to find 15².
- 40.If a − b = 3 and ab = 88, what is a² + b²?
Answer key
- 361
- 816
- 11025
- 9984
- 2448
- 4
- 73
- 4
- 2499
- 2809
- 16
- 10609
- 961
- 20
- 441
- 285
- 169
- 82
- 5
- 1
- 289
- 2475
- 729
- 113
- 169
- 1764
- 5329
- 3481
- 5929
- 225
- 256
- 81
- 64
- 64
- 121
- 9408
- 1
- 2496
- 225
- 185
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