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 25².
- 2.Use a² − b² = (a + b)(a − b) to find 32² − 21².
- 3.Use (a − b)² = a² − 2ab + b² to find 11².
- 4.Find the value of x² − 2xy + y² when x = 12 and y = 9.
- 5.If a − b = 1 and ab = 12, what is a² + b²?
- 6.If a + b = 12 and ab = 35, what is a² + b²?
- 7.Use (a − b)² = a² − 2ab + b² to find 18².
- 8.Use (a + b)² = a² + 2ab + b² to find 74².
- 9.Use (a + b)² = a² + 2ab + b² to find 53².
- 10.If a + b = 11 and ab = 18, what is a² + b²?
- 11.Use (a − b)² = a² − 2ab + b² to find 21².
- 12.If a − b = 1 and ab = 2, what is a² + b²?
- 13.Find the value of x² + 2xy + y² when x = 12 and y = 5.
- 14.Use (a + b)² = a² + 2ab + b² to find 56².
- 15.Use (a + b)² = a² + 2ab + b² to find 39².
- 16.Use (a − b)² = a² − 2ab + b² to find 19².
- 17.Find the value of x² − y² when x = 12 and y = 7.
- 18.If a − b = 2 and ab = 3, what is a² + b²?
- 19.Find the value of x² − 2xy + y² when x = 11 and y = 7.
- 20.Use (a − b)² = a² − 2ab + b² to find 38².
- 21.If a − b = 1 and ab = 20, what is a² + b²?
- 22.Use (a − b)² = a² − 2ab + b² to find 98².
- 23.Use (a + b)(a − b) = a² − b² to find 53 × 47.
- 24.If a + b = 5 and ab = 4, what is a² + b²?
- 25.Use (a − b)² = a² − 2ab + b² to find 74².
- 26.Use a² − b² = (a + b)(a − b) to find 42² − 11².
- 27.Use (a + b)² = a² + 2ab + b² to find 16².
- 28.If a + b = 15 and ab = 44, what is a² + b²?
- 29.Use a² − b² = (a + b)(a − b) to find 38² − 31².
- 30.Use a² − b² = (a + b)(a − b) to find 37² − 28².
- 31.If a + b = 6 and ab = 5, what is a² + b²?
- 32.Find the value of x² − y² when x = 4 and y = 2.
- 33.Use (a − b)² = a² − 2ab + b² to find 15².
- 34.Use (a + b)(a − b) = a² − b² to find 63 × 57.
- 35.If a − b = 5 and ab = 36, what is a² + b²?
- 36.Find the value of x² − 2xy + y² when x = 11 and y = 1.
- 37.Use a² − b² = (a + b)(a − b) to find 33² − 12².
- 38.Use (a − b)² = a² − 2ab + b² to find 76².
- 39.Use (a − b)² = a² − 2ab + b² to find 71².
- 40.Use (a − b)² = a² − 2ab + b² to find 73².
Answer key
- 625
- 583
- 121
- 9
- 25
- 74
- 324
- 5476
- 2809
- 85
- 441
- 5
- 289
- 3136
- 1521
- 361
- 95
- 10
- 16
- 1444
- 41
- 9604
- 2491
- 17
- 5476
- 1643
- 256
- 137
- 483
- 585
- 26
- 12
- 225
- 3591
- 97
- 100
- 945
- 5776
- 5041
- 5329
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