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 51².
- 2.Use (a + b)² = a² + 2ab + b² to find 13².
- 3.Use (a − b)² = a² − 2ab + b² to find 28².
- 4.Find the value of x² − 2xy + y² when x = 6 and y = 1.
- 5.If a − b = 1 and ab = 2, what is a² + b²?
- 6.Use (a − b)² = a² − 2ab + b² to find 29².
- 7.Use (a + b)(a − b) = a² − b² to find 55 × 45.
- 8.Use (a + b)(a − b) = a² − b² to find 81 × 79.
- 9.Use (a + b)² = a² + 2ab + b² to find 62².
- 10.Use (a + b)² = a² + 2ab + b² to find 86².
- 11.Use (a + b)² = a² + 2ab + b² to find 29².
- 12.Use (a − b)² = a² − 2ab + b² to find 88².
- 13.If a − b = 2 and ab = 8, what is a² + b²?
- 14.If a + b = 13 and ab = 40, what is a² + b²?
- 15.If a − b = 4 and ab = 45, what is a² + b²?
- 16.Use (a + b)(a − b) = a² − b² to find 47 × 33.
- 17.Use (a − b)² = a² − 2ab + b² to find 32².
- 18.Use (a − b)² = a² − 2ab + b² to find 58².
- 19.If a + b = 14 and ab = 33, what is a² + b²?
- 20.Use (a + b)² = a² + 2ab + b² to find 74².
- 21.Find the value of x² + 2xy + y² when x = 3 and y = 2.
- 22.Use (a + b)(a − b) = a² − b² to find 74 × 66.
- 23.Find the value of x² − y² when x = 5 and y = 4.
- 24.Use (a + b)(a − b) = a² − b² to find 71 × 69.
- 25.Use (a + b)² = a² + 2ab + b² to find 36².
- 26.Use (a − b)² = a² − 2ab + b² to find 35².
- 27.If a + b = 5 and ab = 6, what is a² + b²?
- 28.If a − b = 6 and ab = 16, what is a² + b²?
- 29.Use (a + b)² = a² + 2ab + b² to find 44².
- 30.Use a² − b² = (a + b)(a − b) to find 93² − 67².
- 31.Use (a + b)² = a² + 2ab + b² to find 82².
- 32.Use (a + b)² = a² + 2ab + b² to find 37².
- 33.Use (a − b)² = a² − 2ab + b² to find 19².
- 34.Use a² − b² = (a + b)(a − b) to find 26² − 25².
- 35.Find the value of x² + 2xy + y² when x = 14 and y = 5.
- 36.Find the value of x² + 2xy + y² when x = 12 and y = 11.
- 37.If a + b = 16 and ab = 55, what is a² + b²?
- 38.Use a² − b² = (a + b)(a − b) to find 54² − 10².
- 39.Find the value of x² + 2xy + y² when x = 4 and y = 3.
- 40.Use (a + b)(a − b) = a² − b² to find 24 × 16.
Answer key
- 2601
- 169
- 784
- 25
- 5
- 841
- 2475
- 6399
- 3844
- 7396
- 841
- 7744
- 20
- 89
- 106
- 1551
- 1024
- 3364
- 130
- 5476
- 25
- 4884
- 9
- 4899
- 1296
- 1225
- 13
- 68
- 1936
- 4160
- 6724
- 1369
- 361
- 51
- 361
- 529
- 146
- 2816
- 49
- 384
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