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 16².
- 2.Find the value of x² + 2xy + y² when x = 13 and y = 8.
- 3.Use (a − b)² = a² − 2ab + b² to find 17².
- 4.Use (a + b)(a − b) = a² − b² to find 43 × 37.
- 5.Use (a + b)(a − b) = a² − b² to find 21 × 19.
- 6.Use a² − b² = (a + b)(a − b) to find 68² − 27².
- 7.Use a² − b² = (a + b)(a − b) to find 55² − 54².
- 8.Use a² − b² = (a + b)(a − b) to find 43² − 35².
- 9.Use (a + b)² = a² + 2ab + b² to find 79².
- 10.Find the value of x² + 2xy + y² when x = 3 and y = 1.
- 11.Use (a + b)(a − b) = a² − b² to find 48 × 32.
- 12.Use (a + b)² = a² + 2ab + b² to find 29².
- 13.Use (a + b)² = a² + 2ab + b² to find 41².
- 14.If a + b = 14 and ab = 33, what is a² + b²?
- 15.Use a² − b² = (a + b)(a − b) to find 83² − 27².
- 16.Use (a − b)² = a² − 2ab + b² to find 75².
- 17.Use (a + b)(a − b) = a² − b² to find 98 × 82.
- 18.Use (a + b)² = a² + 2ab + b² to find 31².
- 19.Use (a + b)² = a² + 2ab + b² to find 11².
- 20.Use (a + b)² = a² + 2ab + b² to find 71².
- 21.Use (a − b)² = a² − 2ab + b² to find 31².
- 22.Use (a − b)² = a² − 2ab + b² to find 51².
- 23.If a − b = 8 and ab = 9, what is a² + b²?
- 24.Find the value of x² − y² when x = 4 and y = 1.
- 25.Find the value of x² − y² when x = 8 and y = 4.
- 26.If a + b = 7 and ab = 10, what is a² + b²?
- 27.Find the value of x² − y² when x = 14 and y = 7.
- 28.If a − b = 1 and ab = 2, what is a² + b²?
- 29.Use (a − b)² = a² − 2ab + b² to find 19².
- 30.Use (a − b)² = a² − 2ab + b² to find 29².
- 31.Find the value of x² + 2xy + y² when x = 10 and y = 9.
- 32.Use a² − b² = (a + b)(a − b) to find 58² − 4².
- 33.Use (a − b)² = a² − 2ab + b² to find 96².
- 34.If a − b = 8 and ab = 33, what is a² + b²?
- 35.If a + b = 9 and ab = 20, what is a² + b²?
- 36.Use (a + b)² = a² + 2ab + b² to find 61².
- 37.Find the value of x² − 2xy + y² when x = 9 and y = 2.
- 38.If a − b = 2 and ab = 8, what is a² + b²?
- 39.Use (a − b)² = a² − 2ab + b² to find 84².
- 40.If a + b = 3 and ab = 2, what is a² + b²?
Answer key
- 256
- 441
- 289
- 1591
- 399
- 3895
- 109
- 624
- 6241
- 16
- 1536
- 841
- 1681
- 130
- 6160
- 5625
- 8036
- 961
- 121
- 5041
- 961
- 2601
- 82
- 15
- 48
- 29
- 147
- 5
- 361
- 841
- 361
- 3348
- 9216
- 130
- 41
- 3721
- 49
- 20
- 7056
- 5
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