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)(a − b) = a² − b² to find 26 × 14.
- 2.Use a² − b² = (a + b)(a − b) to find 52² − 50².
- 3.Use a² − b² = (a + b)(a − b) to find 63² − 36².
- 4.If a − b = 2 and ab = 3, what is a² + b²?
- 5.Use (a + b)² = a² + 2ab + b² to find 23².
- 6.Use (a − b)² = a² − 2ab + b² to find 37².
- 7.Find the value of x² − y² when x = 11 and y = 10.
- 8.Use (a − b)² = a² − 2ab + b² to find 57².
- 9.Use (a + b)(a − b) = a² − b² to find 87 × 73.
- 10.Find the value of x² − y² when x = 9 and y = 8.
- 11.Use a² − b² = (a + b)(a − b) to find 86² − 66².
- 12.If a + b = 13 and ab = 42, what is a² + b²?
- 13.Use a² − b² = (a + b)(a − b) to find 45² − 17².
- 14.Use (a − b)² = a² − 2ab + b² to find 65².
- 15.Use (a − b)² = a² − 2ab + b² to find 89².
- 16.If a − b = 1 and ab = 12, what is a² + b²?
- 17.Use (a + b)² = a² + 2ab + b² to find 18².
- 18.Use (a + b)(a − b) = a² − b² to find 104 × 96.
- 19.Use a² − b² = (a + b)(a − b) to find 72² − 67².
- 20.Find the value of x² + 2xy + y² when x = 9 and y = 2.
- 21.Use (a + b)² = a² + 2ab + b² to find 51².
- 22.Use (a + b)(a − b) = a² − b² to find 41 × 39.
- 23.Find the value of x² − y² when x = 4 and y = 3.
- 24.Use a² − b² = (a + b)(a − b) to find 96² − 65².
- 25.If a − b = 4 and ab = 32, what is a² + b²?
- 26.Use a² − b² = (a + b)(a − b) to find 98² − 10².
- 27.Use a² − b² = (a + b)(a − b) to find 45² − 33².
- 28.Find the value of x² − 2xy + y² when x = 9 and y = 5.
- 29.If a + b = 13 and ab = 30, what is a² + b²?
- 30.Use (a + b)² = a² + 2ab + b² to find 15².
- 31.Use (a − b)² = a² − 2ab + b² to find 25².
- 32.If a + b = 5 and ab = 4, what is a² + b²?
- 33.Use (a − b)² = a² − 2ab + b² to find 92².
- 34.Use (a + b)(a − b) = a² − b² to find 53 × 47.
- 35.Use (a + b)² = a² + 2ab + b² to find 101².
- 36.If a − b = 2 and ab = 24, what is a² + b²?
- 37.Use (a − b)² = a² − 2ab + b² to find 17².
- 38.Use (a − b)² = a² − 2ab + b² to find 52².
- 39.Use a² − b² = (a + b)(a − b) to find 69² − 28².
- 40.Use (a + b)² = a² + 2ab + b² to find 12².
Answer key
- 364
- 204
- 2673
- 10
- 529
- 1369
- 21
- 3249
- 6351
- 17
- 3040
- 85
- 1736
- 4225
- 7921
- 25
- 324
- 9984
- 695
- 121
- 2601
- 1599
- 7
- 4991
- 80
- 9504
- 936
- 16
- 109
- 225
- 625
- 17
- 8464
- 2491
- 10201
- 52
- 289
- 2704
- 3977
- 144
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