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 a² − b² = (a + b)(a − b) to find 66² − 29².
- 2.Find the value of x² − 2xy + y² when x = 6 and y = 5.
- 3.Use (a + b)² = a² + 2ab + b² to find 15².
- 4.Use (a − b)² = a² − 2ab + b² to find 82².
- 5.If a − b = 3 and ab = 18, what is a² + b²?
- 6.Use a² − b² = (a + b)(a − b) to find 20² − 19².
- 7.Use (a − b)² = a² − 2ab + b² to find 83².
- 8.Use (a + b)² = a² + 2ab + b² to find 85².
- 9.Use a² − b² = (a + b)(a − b) to find 33² − 24².
- 10.Find the value of x² + 2xy + y² when x = 9 and y = 1.
- 11.Find the value of x² − y² when x = 7 and y = 1.
- 12.Use a² − b² = (a + b)(a − b) to find 25² − 7².
- 13.Use (a + b)² = a² + 2ab + b² to find 68².
- 14.Find the value of x² + 2xy + y² when x = 10 and y = 6.
- 15.Use a² − b² = (a + b)(a − b) to find 86² − 13².
- 16.Use (a − b)² = a² − 2ab + b² to find 71².
- 17.Use (a + b)(a − b) = a² − b² to find 95 × 85.
- 18.Use (a + b)(a − b) = a² − b² to find 83 × 77.
- 19.Use (a + b)² = a² + 2ab + b² to find 88².
- 20.Use (a + b)(a − b) = a² − b² to find 44 × 36.
- 21.Find the value of x² − 2xy + y² when x = 7 and y = 4.
- 22.Use a² − b² = (a + b)(a − b) to find 68² − 62².
- 23.Find the value of x² − 2xy + y² when x = 6 and y = 3.
- 24.Use (a + b)(a − b) = a² − b² to find 23 × 17.
- 25.Use (a + b)² = a² + 2ab + b² to find 82².
- 26.If a + b = 3 and ab = 2, what is a² + b²?
- 27.Use (a + b)² = a² + 2ab + b² to find 26².
- 28.Find the value of x² − y² when x = 10 and y = 2.
- 29.Use (a + b)(a − b) = a² − b² to find 58 × 42.
- 30.Use (a + b)² = a² + 2ab + b² to find 52².
- 31.Use a² − b² = (a + b)(a − b) to find 72² − 56².
- 32.If a + b = 15 and ab = 56, what is a² + b²?
- 33.Use a² − b² = (a + b)(a − b) to find 81² − 51².
- 34.Use (a + b)² = a² + 2ab + b² to find 37².
- 35.Find the value of x² + 2xy + y² when x = 6 and y = 1.
- 36.Find the value of x² − 2xy + y² when x = 14 and y = 4.
- 37.Use a² − b² = (a + b)(a − b) to find 97² − 63².
- 38.Use a² − b² = (a + b)(a − b) to find 84² − 62².
- 39.Use (a + b)² = a² + 2ab + b² to find 45².
- 40.Find the value of x² − 2xy + y² when x = 12 and y = 3.
Answer key
- 3515
- 1
- 225
- 6724
- 45
- 39
- 6889
- 7225
- 513
- 100
- 48
- 576
- 4624
- 256
- 7227
- 5041
- 8075
- 6391
- 7744
- 1584
- 9
- 780
- 9
- 391
- 6724
- 5
- 676
- 96
- 2436
- 2704
- 2048
- 113
- 3960
- 1369
- 49
- 100
- 5440
- 3212
- 2025
- 81
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