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 35².
- 2.Use (a − b)² = a² − 2ab + b² to find 37².
- 3.Find the value of x² − y² when x = 5 and y = 3.
- 4.Use (a − b)² = a² − 2ab + b² to find 92².
- 5.If a − b = 1 and ab = 2, what is a² + b²?
- 6.Use (a + b)(a − b) = a² − b² to find 95 × 85.
- 7.Use (a − b)² = a² − 2ab + b² to find 79².
- 8.Use (a + b)(a − b) = a² − b² to find 98 × 82.
- 9.Find the value of x² + 2xy + y² when x = 12 and y = 4.
- 10.Use (a + b)² = a² + 2ab + b² to find 75².
- 11.Use (a + b)² = a² + 2ab + b² to find 105².
- 12.Use (a + b)² = a² + 2ab + b² to find 56².
- 13.Find the value of x² + 2xy + y² when x = 7 and y = 5.
- 14.Find the value of x² − y² when x = 3 and y = 1.
- 15.Use (a − b)² = a² − 2ab + b² to find 43².
- 16.Use (a + b)² = a² + 2ab + b² to find 86².
- 17.Use (a + b)² = a² + 2ab + b² to find 62².
- 18.Find the value of x² − 2xy + y² when x = 6 and y = 5.
- 19.Find the value of x² − 2xy + y² when x = 4 and y = 1.
- 20.Use a² − b² = (a + b)(a − b) to find 41² − 9².
- 21.Use (a − b)² = a² − 2ab + b² to find 28².
- 22.Use (a + b)² = a² + 2ab + b² to find 23².
- 23.Find the value of x² − y² when x = 11 and y = 5.
- 24.Use (a + b)² = a² + 2ab + b² to find 61².
- 25.Use a² − b² = (a + b)(a − b) to find 60² − 2².
- 26.Use (a − b)² = a² − 2ab + b² to find 97².
- 27.Find the value of x² + 2xy + y² when x = 3 and y = 2.
- 28.Find the value of x² − 2xy + y² when x = 14 and y = 2.
- 29.Find the value of x² − y² when x = 15 and y = 14.
- 30.Use (a + b)(a − b) = a² − b² to find 27 × 13.
- 31.Use (a + b)² = a² + 2ab + b² to find 91².
- 32.If a + b = 9 and ab = 8, what is a² + b²?
- 33.Use (a + b)² = a² + 2ab + b² to find 77².
- 34.Use (a + b)(a − b) = a² − b² to find 44 × 36.
- 35.Use a² − b² = (a + b)(a − b) to find 20² − 2².
- 36.Find the value of x² − y² when x = 14 and y = 2.
- 37.Use a² − b² = (a + b)(a − b) to find 73² − 7².
- 38.If a − b = 7 and ab = 30, what is a² + b²?
- 39.If a − b = 6 and ab = 27, what is a² + b²?
- 40.Use (a + b)(a − b) = a² − b² to find 47 × 33.
Answer key
- 1225
- 1369
- 16
- 8464
- 5
- 8075
- 6241
- 8036
- 256
- 5625
- 11025
- 3136
- 144
- 8
- 1849
- 7396
- 3844
- 1
- 9
- 1600
- 784
- 529
- 96
- 3721
- 3596
- 9409
- 25
- 144
- 29
- 351
- 8281
- 65
- 5929
- 1584
- 396
- 192
- 5280
- 109
- 90
- 1551
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