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 22².
- 2.If a − b = 4 and ab = 5, what is a² + b²?
- 3.Use (a + b)² = a² + 2ab + b² to find 68².
- 4.Use (a + b)² = a² + 2ab + b² to find 64².
- 5.Find the value of x² − 2xy + y² when x = 7 and y = 2.
- 6.Use (a + b)² = a² + 2ab + b² to find 37².
- 7.Use a² − b² = (a + b)(a − b) to find 50² − 5².
- 8.Use (a + b)² = a² + 2ab + b² to find 32².
- 9.Use (a + b)² = a² + 2ab + b² to find 31².
- 10.If a + b = 5 and ab = 4, what is a² + b²?
- 11.Use (a + b)² = a² + 2ab + b² to find 24².
- 12.Find the value of x² − y² when x = 15 and y = 14.
- 13.If a − b = 1 and ab = 6, what is a² + b²?
- 14.If a − b = 2 and ab = 3, what is a² + b²?
- 15.Use (a + b)(a − b) = a² − b² to find 27 × 13.
- 16.Use (a + b)² = a² + 2ab + b² to find 88².
- 17.Find the value of x² − 2xy + y² when x = 10 and y = 2.
- 18.Use a² − b² = (a + b)(a − b) to find 53² − 47².
- 19.If a + b = 6 and ab = 5, what is a² + b²?
- 20.Use (a + b)² = a² + 2ab + b² to find 97².
- 21.Use a² − b² = (a + b)(a − b) to find 29² − 5².
- 22.Use (a + b)(a − b) = a² − b² to find 93 × 87.
- 23.Find the value of x² − 2xy + y² when x = 10 and y = 1.
- 24.Use a² − b² = (a + b)(a − b) to find 39² − 10².
- 25.Use (a + b)(a − b) = a² − b² to find 79 × 61.
- 26.If a + b = 9 and ab = 8, what is a² + b²?
- 27.Use (a − b)² = a² − 2ab + b² to find 32².
- 28.If a + b = 3 and ab = 2, what is a² + b²?
- 29.Use a² − b² = (a + b)(a − b) to find 34² − 30².
- 30.Use (a + b)² = a² + 2ab + b² to find 26².
- 31.Use a² − b² = (a + b)(a − b) to find 57² − 14².
- 32.Use (a + b)(a − b) = a² − b² to find 41 × 39.
- 33.Use (a − b)² = a² − 2ab + b² to find 44².
- 34.Use (a + b)² = a² + 2ab + b² to find 12².
- 35.Use a² − b² = (a + b)(a − b) to find 82² − 13².
- 36.Use a² − b² = (a + b)(a − b) to find 32² − 1².
- 37.Use (a − b)² = a² − 2ab + b² to find 37².
- 38.Use (a + b)(a − b) = a² − b² to find 105 × 95.
- 39.If a + b = 15 and ab = 44, what is a² + b²?
- 40.Use (a + b)(a − b) = a² − b² to find 49 × 31.
Answer key
- 484
- 26
- 4624
- 4096
- 25
- 1369
- 2475
- 1024
- 961
- 17
- 576
- 29
- 13
- 10
- 351
- 7744
- 64
- 600
- 26
- 9409
- 816
- 8091
- 81
- 1421
- 4819
- 65
- 1024
- 5
- 256
- 676
- 3053
- 1599
- 1936
- 144
- 6555
- 1023
- 1369
- 9975
- 137
- 1519
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