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 82².
- 2.Use (a + b)(a − b) = a² − b² to find 48 × 32.
- 3.Find the value of x² − 2xy + y² when x = 10 and y = 1.
- 4.If a − b = 8 and ab = 33, what is a² + b²?
- 5.Use (a − b)² = a² − 2ab + b² to find 37².
- 6.Find the value of x² − y² when x = 6 and y = 3.
- 7.If a + b = 3 and ab = 2, what is a² + b²?
- 8.Use (a + b)² = a² + 2ab + b² to find 41².
- 9.Use a² − b² = (a + b)(a − b) to find 39² − 36².
- 10.Find the value of x² − 2xy + y² when x = 5 and y = 3.
- 11.Find the value of x² − 2xy + y² when x = 14 and y = 9.
- 12.If a − b = 2 and ab = 3, what is a² + b²?
- 13.Use (a + b)² = a² + 2ab + b² to find 103².
- 14.Use (a − b)² = a² − 2ab + b² to find 69².
- 15.Find the value of x² + 2xy + y² when x = 13 and y = 6.
- 16.Use (a − b)² = a² − 2ab + b² to find 54².
- 17.Use a² − b² = (a + b)(a − b) to find 87² − 86².
- 18.Use (a + b)(a − b) = a² − b² to find 107 × 93.
- 19.Find the value of x² − y² when x = 6 and y = 4.
- 20.Find the value of x² − 2xy + y² when x = 7 and y = 4.
- 21.Find the value of x² + 2xy + y² when x = 14 and y = 10.
- 22.If a + b = 20 and ab = 96, what is a² + b²?
- 23.Use (a + b)(a − b) = a² − b² to find 108 × 92.
- 24.Use (a + b)² = a² + 2ab + b² to find 83².
- 25.Use a² − b² = (a + b)(a − b) to find 61² − 16².
- 26.Use (a + b)² = a² + 2ab + b² to find 67².
- 27.If a + b = 13 and ab = 36, what is a² + b²?
- 28.Find the value of x² − y² when x = 15 and y = 13.
- 29.Use (a + b)² = a² + 2ab + b² to find 14².
- 30.Use (a + b)(a − b) = a² − b² to find 41 × 39.
- 31.Use a² − b² = (a + b)(a − b) to find 55² − 41².
- 32.Use (a − b)² = a² − 2ab + b² to find 38².
- 33.Use (a + b)² = a² + 2ab + b² to find 38².
- 34.Use (a + b)² = a² + 2ab + b² to find 104².
- 35.Use (a − b)² = a² − 2ab + b² to find 47².
- 36.Use (a + b)(a − b) = a² − b² to find 109 × 91.
- 37.Use (a + b)² = a² + 2ab + b² to find 45².
- 38.Use (a − b)² = a² − 2ab + b² to find 76².
- 39.Find the value of x² + 2xy + y² when x = 5 and y = 3.
- 40.Use a² − b² = (a + b)(a − b) to find 62² − 25².
Answer key
- 6724
- 1536
- 81
- 130
- 1369
- 27
- 5
- 1681
- 225
- 4
- 25
- 10
- 10609
- 4761
- 361
- 2916
- 173
- 9951
- 20
- 9
- 576
- 208
- 9936
- 6889
- 3465
- 4489
- 97
- 56
- 196
- 1599
- 1344
- 1444
- 1444
- 10816
- 2209
- 9919
- 2025
- 5776
- 64
- 3219
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