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 31².
- 2.If a − b = 1 and ab = 12, what is a² + b²?
- 3.Find the value of x² + 2xy + y² when x = 9 and y = 1.
- 4.Find the value of x² − y² when x = 15 and y = 1.
- 5.Find the value of x² − y² when x = 5 and y = 1.
- 6.Find the value of x² − 2xy + y² when x = 4 and y = 1.
- 7.Use (a − b)² = a² − 2ab + b² to find 37².
- 8.Use (a − b)² = a² − 2ab + b² to find 58².
- 9.Use (a + b)(a − b) = a² − b² to find 55 × 45.
- 10.Use (a + b)² = a² + 2ab + b² to find 102².
- 11.If a + b = 22 and ab = 120, what is a² + b²?
- 12.Use a² − b² = (a + b)(a − b) to find 43² − 38².
- 13.If a + b = 6 and ab = 5, what is a² + b²?
- 14.If a + b = 4 and ab = 3, what is a² + b²?
- 15.If a + b = 5 and ab = 4, what is a² + b²?
- 16.Use (a + b)² = a² + 2ab + b² to find 57².
- 17.Find the value of x² + 2xy + y² when x = 6 and y = 3.
- 18.Use a² − b² = (a + b)(a − b) to find 89² − 8².
- 19.If a − b = 4 and ab = 32, what is a² + b²?
- 20.Use (a − b)² = a² − 2ab + b² to find 68².
- 21.Find the value of x² − y² when x = 6 and y = 5.
- 22.Use (a + b)² = a² + 2ab + b² to find 96².
- 23.Find the value of x² − 2xy + y² when x = 9 and y = 4.
- 24.Use (a + b)² = a² + 2ab + b² to find 63².
- 25.Use (a − b)² = a² − 2ab + b² to find 11².
- 26.Use a² − b² = (a + b)(a − b) to find 51² − 2².
- 27.Use (a + b)² = a² + 2ab + b² to find 11².
- 28.Use a² − b² = (a + b)(a − b) to find 96² − 12².
- 29.Use (a − b)² = a² − 2ab + b² to find 17².
- 30.Use a² − b² = (a + b)(a − b) to find 33² − 6².
- 31.Use (a − b)² = a² − 2ab + b² to find 29².
- 32.If a − b = 2 and ab = 15, what is a² + b²?
- 33.Find the value of x² − y² when x = 10 and y = 1.
- 34.Find the value of x² + 2xy + y² when x = 7 and y = 2.
- 35.If a + b = 8 and ab = 15, what is a² + b²?
- 36.Use (a − b)² = a² − 2ab + b² to find 56².
- 37.Use (a + b)(a − b) = a² − b² to find 45 × 35.
- 38.Find the value of x² − y² when x = 13 and y = 11.
- 39.Use (a − b)² = a² − 2ab + b² to find 31².
- 40.If a − b = 1 and ab = 6, what is a² + b²?
Answer key
- 961
- 25
- 100
- 224
- 24
- 9
- 1369
- 3364
- 2475
- 10404
- 244
- 405
- 26
- 10
- 17
- 3249
- 81
- 7857
- 80
- 4624
- 11
- 9216
- 25
- 3969
- 121
- 2597
- 121
- 9072
- 289
- 1053
- 841
- 34
- 99
- 81
- 34
- 3136
- 1575
- 48
- 961
- 13
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