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 = 4 and y = 3.
- 2.Find the value of x² − y² when x = 5 and y = 4.
- 3.Use (a − b)² = a² − 2ab + b² to find 31².
- 4.Use a² − b² = (a + b)(a − b) to find 88² − 33².
- 5.Use (a + b)² = a² + 2ab + b² to find 33².
- 6.Find the value of x² − y² when x = 4 and y = 3.
- 7.Find the value of x² + 2xy + y² when x = 9 and y = 3.
- 8.Use (a + b)(a − b) = a² − b² to find 85 × 75.
- 9.Use (a + b)² = a² + 2ab + b² to find 101².
- 10.Find the value of x² + 2xy + y² when x = 8 and y = 3.
- 11.Use (a + b)(a − b) = a² − b² to find 49 × 31.
- 12.Use (a − b)² = a² − 2ab + b² to find 66².
- 13.Use (a + b)(a − b) = a² − b² to find 72 × 68.
- 14.Use (a − b)² = a² − 2ab + b² to find 87².
- 15.Use (a − b)² = a² − 2ab + b² to find 21².
- 16.Use (a + b)² = a² + 2ab + b² to find 82².
- 17.Use (a + b)(a − b) = a² − b² to find 39 × 21.
- 18.If a − b = 3 and ab = 40, what is a² + b²?
- 19.Use (a − b)² = a² − 2ab + b² to find 77².
- 20.Find the value of x² − y² when x = 7 and y = 4.
- 21.Use a² − b² = (a + b)(a − b) to find 41² − 2².
- 22.If a − b = 1 and ab = 42, what is a² + b²?
- 23.Use (a + b)² = a² + 2ab + b² to find 61².
- 24.Use (a + b)(a − b) = a² − b² to find 54 × 46.
- 25.Use (a + b)² = a² + 2ab + b² to find 35².
- 26.Use (a + b)(a − b) = a² − b² to find 104 × 96.
- 27.If a + b = 4 and ab = 3, what is a² + b²?
- 28.Use (a + b)(a − b) = a² − b² to find 22 × 18.
- 29.Use (a − b)² = a² − 2ab + b² to find 88².
- 30.If a + b = 9 and ab = 8, what is a² + b²?
- 31.Use (a + b)² = a² + 2ab + b² to find 28².
- 32.Find the value of x² + 2xy + y² when x = 9 and y = 8.
- 33.Use (a − b)² = a² − 2ab + b² to find 86².
- 34.Use (a − b)² = a² − 2ab + b² to find 11².
- 35.Use (a + b)(a − b) = a² − b² to find 67 × 53.
- 36.If a + b = 11 and ab = 18, what is a² + b²?
- 37.Find the value of x² + 2xy + y² when x = 9 and y = 1.
- 38.Use (a − b)² = a² − 2ab + b² to find 29².
- 39.Use (a − b)² = a² − 2ab + b² to find 96².
- 40.Find the value of x² − 2xy + y² when x = 7 and y = 3.
Answer key
- 49
- 9
- 961
- 6655
- 1089
- 7
- 144
- 6375
- 10201
- 121
- 1519
- 4356
- 4896
- 7569
- 441
- 6724
- 819
- 89
- 5929
- 33
- 1677
- 85
- 3721
- 2484
- 1225
- 9984
- 10
- 396
- 7744
- 65
- 784
- 289
- 7396
- 121
- 3551
- 85
- 100
- 841
- 9216
- 16
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