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 − 2xy + y² when x = 3 and y = 2.
- 2.Find the value of x² − 2xy + y² when x = 6 and y = 2.
- 3.If a − b = 1 and ab = 2, what is a² + b²?
- 4.Use (a − b)² = a² − 2ab + b² to find 67².
- 5.If a + b = 9 and ab = 8, what is a² + b²?
- 6.Find the value of x² − 2xy + y² when x = 5 and y = 3.
- 7.Use a² − b² = (a + b)(a − b) to find 78² − 39².
- 8.Find the value of x² + 2xy + y² when x = 5 and y = 2.
- 9.If a + b = 12 and ab = 32, what is a² + b²?
- 10.Find the value of x² + 2xy + y² when x = 14 and y = 10.
- 11.Use (a + b)(a − b) = a² − b² to find 43 × 37.
- 12.If a + b = 14 and ab = 33, what is a² + b²?
- 13.Use (a + b)² = a² + 2ab + b² to find 78².
- 14.If a − b = 2 and ab = 24, what is a² + b²?
- 15.Use a² − b² = (a + b)(a − b) to find 22² − 12².
- 16.Find the value of x² − y² when x = 15 and y = 4.
- 17.Use (a + b)(a − b) = a² − b² to find 68 × 52.
- 18.If a − b = 1 and ab = 12, what is a² + b²?
- 19.If a − b = 3 and ab = 108, what is a² + b²?
- 20.Use (a + b)(a − b) = a² − b² to find 93 × 87.
- 21.If a − b = 1 and ab = 110, what is a² + b²?
- 22.Find the value of x² + 2xy + y² when x = 11 and y = 3.
- 23.If a + b = 3 and ab = 2, what is a² + b²?
- 24.Use (a + b)(a − b) = a² − b² to find 92 × 88.
- 25.Use (a + b)² = a² + 2ab + b² to find 81².
- 26.Find the value of x² + 2xy + y² when x = 3 and y = 2.
- 27.Use (a − b)² = a² − 2ab + b² to find 52².
- 28.Use (a + b)² = a² + 2ab + b² to find 48².
- 29.Use (a + b)(a − b) = a² − b² to find 39 × 21.
- 30.Use (a − b)² = a² − 2ab + b² to find 58².
- 31.Use a² − b² = (a + b)(a − b) to find 24² − 17².
- 32.Use (a − b)² = a² − 2ab + b² to find 18².
- 33.Use (a − b)² = a² − 2ab + b² to find 45².
- 34.Find the value of x² + 2xy + y² when x = 4 and y = 3.
- 35.Use (a − b)² = a² − 2ab + b² to find 38².
- 36.Use (a + b)(a − b) = a² − b² to find 104 × 96.
- 37.Use (a + b)² = a² + 2ab + b² to find 21².
- 38.If a − b = 2 and ab = 3, what is a² + b²?
- 39.Find the value of x² − 2xy + y² when x = 10 and y = 4.
- 40.Use a² − b² = (a + b)(a − b) to find 35² − 15².
Answer key
- 1
- 16
- 5
- 4489
- 65
- 4
- 4563
- 49
- 80
- 576
- 1591
- 130
- 6084
- 52
- 340
- 209
- 3536
- 25
- 225
- 8091
- 221
- 196
- 5
- 8096
- 6561
- 25
- 2704
- 2304
- 819
- 3364
- 287
- 324
- 2025
- 49
- 1444
- 9984
- 441
- 10
- 36
- 1000
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