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 41².
- 2.Use (a + b)² = a² + 2ab + b² to find 81².
- 3.Use (a + b)² = a² + 2ab + b² to find 91².
- 4.Use (a + b)(a − b) = a² − b² to find 42 × 38.
- 5.Use (a + b)(a − b) = a² − b² to find 44 × 36.
- 6.Use (a − b)² = a² − 2ab + b² to find 84².
- 7.If a + b = 8 and ab = 15, what is a² + b²?
- 8.Use (a + b)² = a² + 2ab + b² to find 17².
- 9.Use (a − b)² = a² − 2ab + b² to find 56².
- 10.Use a² − b² = (a + b)(a − b) to find 28² − 14².
- 11.Use (a − b)² = a² − 2ab + b² to find 82².
- 12.Use (a + b)(a − b) = a² − b² to find 73 × 67.
- 13.Find the value of x² − y² when x = 10 and y = 3.
- 14.Use (a − b)² = a² − 2ab + b² to find 38².
- 15.Use a² − b² = (a + b)(a − b) to find 46² − 2².
- 16.Use (a + b)(a − b) = a² − b² to find 53 × 47.
- 17.Use a² − b² = (a + b)(a − b) to find 37² − 6².
- 18.Find the value of x² − y² when x = 9 and y = 7.
- 19.Use (a + b)² = a² + 2ab + b² to find 16².
- 20.Use (a + b)² = a² + 2ab + b² to find 59².
- 21.Use (a − b)² = a² − 2ab + b² to find 26².
- 22.Find the value of x² + 2xy + y² when x = 5 and y = 4.
- 23.If a − b = 2 and ab = 15, what is a² + b²?
- 24.If a − b = 2 and ab = 3, what is a² + b²?
- 25.Use (a − b)² = a² − 2ab + b² to find 31².
- 26.Use a² − b² = (a + b)(a − b) to find 57² − 52².
- 27.Use (a − b)² = a² − 2ab + b² to find 88².
- 28.Use (a − b)² = a² − 2ab + b² to find 41².
- 29.Use a² − b² = (a + b)(a − b) to find 60² − 52².
- 30.Use (a − b)² = a² − 2ab + b² to find 63².
- 31.Use a² − b² = (a + b)(a − b) to find 87² − 52².
- 32.Use (a − b)² = a² − 2ab + b² to find 67².
- 33.Use a² − b² = (a + b)(a − b) to find 33² − 6².
- 34.If a + b = 5 and ab = 6, what is a² + b²?
- 35.Use a² − b² = (a + b)(a − b) to find 97² − 37².
- 36.Use (a + b)(a − b) = a² − b² to find 104 × 96.
- 37.Find the value of x² − y² when x = 8 and y = 5.
- 38.Use (a + b)² = a² + 2ab + b² to find 46².
- 39.Use (a − b)² = a² − 2ab + b² to find 44².
- 40.Use (a − b)² = a² − 2ab + b² to find 78².
Answer key
- 1681
- 6561
- 8281
- 1596
- 1584
- 7056
- 34
- 289
- 3136
- 588
- 6724
- 4891
- 91
- 1444
- 2112
- 2491
- 1333
- 32
- 256
- 3481
- 676
- 81
- 34
- 10
- 961
- 545
- 7744
- 1681
- 896
- 3969
- 4865
- 4489
- 1053
- 13
- 8040
- 9984
- 39
- 2116
- 1936
- 6084
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