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 63².
- 2.Use a² − b² = (a + b)(a − b) to find 45² − 13².
- 3.Use a² − b² = (a + b)(a − b) to find 76² − 1².
- 4.If a − b = 4 and ab = 5, what is a² + b²?
- 5.If a + b = 3 and ab = 2, what is a² + b²?
- 6.Use a² − b² = (a + b)(a − b) to find 64² − 48².
- 7.Use (a − b)² = a² − 2ab + b² to find 45².
- 8.Find the value of x² − y² when x = 6 and y = 2.
- 9.Find the value of x² − y² when x = 8 and y = 5.
- 10.Use (a + b)² = a² + 2ab + b² to find 91².
- 11.Use (a − b)² = a² − 2ab + b² to find 56².
- 12.Find the value of x² + 2xy + y² when x = 10 and y = 1.
- 13.Find the value of x² − y² when x = 7 and y = 2.
- 14.If a − b = 6 and ab = 27, what is a² + b²?
- 15.Use (a + b)² = a² + 2ab + b² to find 58².
- 16.Use (a + b)² = a² + 2ab + b² to find 42².
- 17.Use (a + b)² = a² + 2ab + b² to find 28².
- 18.Find the value of x² − y² when x = 3 and y = 2.
- 19.Use a² − b² = (a + b)(a − b) to find 36² − 27².
- 20.If a + b = 10 and ab = 24, what is a² + b²?
- 21.Use (a − b)² = a² − 2ab + b² to find 38².
- 22.Find the value of x² + 2xy + y² when x = 12 and y = 6.
- 23.Use (a + b)(a − b) = a² − b² to find 41 × 39.
- 24.If a − b = 8 and ab = 9, what is a² + b²?
- 25.Use (a + b)² = a² + 2ab + b² to find 102².
- 26.Find the value of x² − 2xy + y² when x = 12 and y = 2.
- 27.Use (a − b)² = a² − 2ab + b² to find 41².
- 28.Use (a + b)² = a² + 2ab + b² to find 72².
- 29.Use (a − b)² = a² − 2ab + b² to find 67².
- 30.Use (a + b)(a − b) = a² − b² to find 89 × 71.
- 31.Use a² − b² = (a + b)(a − b) to find 73² − 10².
- 32.Use (a + b)² = a² + 2ab + b² to find 56².
- 33.Use (a + b)(a − b) = a² − b² to find 42 × 38.
- 34.Find the value of x² + 2xy + y² when x = 7 and y = 6.
- 35.If a − b = 2 and ab = 80, what is a² + b²?
- 36.Use (a − b)² = a² − 2ab + b² to find 44².
- 37.Use (a − b)² = a² − 2ab + b² to find 16².
- 38.Use (a + b)(a − b) = a² − b² to find 81 × 79.
- 39.Use (a − b)² = a² − 2ab + b² to find 39².
- 40.Find the value of x² + 2xy + y² when x = 14 and y = 2.
Answer key
- 3969
- 1856
- 5775
- 26
- 5
- 1792
- 2025
- 32
- 39
- 8281
- 3136
- 121
- 45
- 90
- 3364
- 1764
- 784
- 5
- 567
- 52
- 1444
- 324
- 1599
- 82
- 10404
- 100
- 1681
- 5184
- 4489
- 6319
- 5229
- 3136
- 1596
- 169
- 164
- 1936
- 256
- 6399
- 1521
- 256
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