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.If a − b = 1 and ab = 2, what is a² + b²?
- 2.Use (a + b)(a − b) = a² − b² to find 53 × 47.
- 3.Find the value of x² − 2xy + y² when x = 8 and y = 3.
- 4.Use a² − b² = (a + b)(a − b) to find 58² − 47².
- 5.Find the value of x² − 2xy + y² when x = 14 and y = 5.
- 6.Use (a + b)² = a² + 2ab + b² to find 38².
- 7.Use (a + b)² = a² + 2ab + b² to find 109².
- 8.Use a² − b² = (a + b)(a − b) to find 46² − 43².
- 9.Use a² − b² = (a + b)(a − b) to find 52² − 15².
- 10.If a + b = 8 and ab = 7, what is a² + b²?
- 11.Find the value of x² − y² when x = 12 and y = 11.
- 12.Find the value of x² − y² when x = 5 and y = 3.
- 13.If a − b = 6 and ab = 16, what is a² + b²?
- 14.Use (a + b)² = a² + 2ab + b² to find 17².
- 15.Use (a − b)² = a² − 2ab + b² to find 98².
- 16.Use (a + b)² = a² + 2ab + b² to find 32².
- 17.Use (a − b)² = a² − 2ab + b² to find 76².
- 18.Use (a − b)² = a² − 2ab + b² to find 46².
- 19.Use (a − b)² = a² − 2ab + b² to find 82².
- 20.Use a² − b² = (a + b)(a − b) to find 37² − 10².
- 21.Use (a + b)² = a² + 2ab + b² to find 88².
- 22.Use (a + b)(a − b) = a² − b² to find 64 × 56.
- 23.Use (a + b)² = a² + 2ab + b² to find 92².
- 24.Find the value of x² + 2xy + y² when x = 6 and y = 2.
- 25.If a + b = 5 and ab = 6, what is a² + b²?
- 26.If a − b = 5 and ab = 6, what is a² + b²?
- 27.Use (a + b)² = a² + 2ab + b² to find 107².
- 28.Use (a + b)² = a² + 2ab + b² to find 85².
- 29.Use (a + b)² = a² + 2ab + b² to find 12².
- 30.Use (a + b)² = a² + 2ab + b² to find 63².
- 31.If a − b = 6 and ab = 72, what is a² + b²?
- 32.Use (a − b)² = a² − 2ab + b² to find 29².
- 33.Use (a + b)(a − b) = a² − b² to find 101 × 99.
- 34.If a − b = 9 and ab = 36, what is a² + b²?
- 35.Use a² − b² = (a + b)(a − b) to find 99² − 12².
- 36.Use (a + b)² = a² + 2ab + b² to find 16².
- 37.Use (a + b)(a − b) = a² − b² to find 34 × 26.
- 38.Use (a − b)² = a² − 2ab + b² to find 37².
- 39.Use (a − b)² = a² − 2ab + b² to find 99².
- 40.Find the value of x² + 2xy + y² when x = 4 and y = 3.
Answer key
- 5
- 2491
- 25
- 1155
- 81
- 1444
- 11881
- 267
- 2479
- 50
- 23
- 16
- 68
- 289
- 9604
- 1024
- 5776
- 2116
- 6724
- 1269
- 7744
- 3584
- 8464
- 64
- 13
- 37
- 11449
- 7225
- 144
- 3969
- 180
- 841
- 9999
- 153
- 9657
- 256
- 884
- 1369
- 9801
- 49
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