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.Find the value of x² − y² when x = 3 and y = 1.
- 2.Use a² − b² = (a + b)(a − b) to find 50² − 4².
- 3.If a + b = 17 and ab = 66, what is a² + b²?
- 4.If a − b = 1 and ab = 2, what is a² + b²?
- 5.Find the value of x² − 2xy + y² when x = 6 and y = 2.
- 6.If a − b = 5 and ab = 6, what is a² + b²?
- 7.Use (a + b)(a − b) = a² − b² to find 22 × 18.
- 8.Use (a − b)² = a² − 2ab + b² to find 69².
- 9.If a + b = 6 and ab = 5, what is a² + b²?
- 10.Use (a + b)² = a² + 2ab + b² to find 102².
- 11.Use (a + b)² = a² + 2ab + b² to find 103².
- 12.Use a² − b² = (a + b)(a − b) to find 83² − 51².
- 13.Use (a − b)² = a² − 2ab + b² to find 31².
- 14.Find the value of x² − 2xy + y² when x = 11 and y = 9.
- 15.Use (a + b)(a − b) = a² − b² to find 32 × 28.
- 16.Use (a + b)² = a² + 2ab + b² to find 46².
- 17.Use a² − b² = (a + b)(a − b) to find 76² − 43².
- 18.Find the value of x² − y² when x = 5 and y = 1.
- 19.Use (a − b)² = a² − 2ab + b² to find 74².
- 20.Use (a + b)(a − b) = a² − b² to find 72 × 68.
- 21.Use (a + b)² = a² + 2ab + b² to find 92².
- 22.Use (a + b)(a − b) = a² − b² to find 59 × 41.
- 23.Find the value of x² + 2xy + y² when x = 4 and y = 1.
- 24.If a + b = 15 and ab = 44, what is a² + b²?
- 25.Find the value of x² + 2xy + y² when x = 7 and y = 5.
- 26.Use a² − b² = (a + b)(a − b) to find 33² − 12².
- 27.Use (a + b)(a − b) = a² − b² to find 33 × 27.
- 28.Use (a + b)² = a² + 2ab + b² to find 25².
- 29.Use (a + b)(a − b) = a² − b² to find 26 × 14.
- 30.Use (a + b)(a − b) = a² − b² to find 42 × 38.
- 31.Use (a − b)² = a² − 2ab + b² to find 34².
- 32.Find the value of x² − y² when x = 6 and y = 2.
- 33.Use (a + b)² = a² + 2ab + b² to find 58².
- 34.Use (a + b)² = a² + 2ab + b² to find 77².
- 35.Use (a + b)² = a² + 2ab + b² to find 88².
- 36.Use (a + b)(a − b) = a² − b² to find 34 × 26.
- 37.If a + b = 14 and ab = 40, what is a² + b²?
- 38.If a − b = 2 and ab = 3, what is a² + b²?
- 39.If a + b = 7 and ab = 12, what is a² + b²?
- 40.Use (a + b)² = a² + 2ab + b² to find 22².
Answer key
- 8
- 2484
- 157
- 5
- 16
- 37
- 396
- 4761
- 26
- 10404
- 10609
- 4288
- 961
- 4
- 896
- 2116
- 3927
- 24
- 5476
- 4896
- 8464
- 2419
- 25
- 137
- 144
- 945
- 891
- 625
- 364
- 1596
- 1156
- 32
- 3364
- 5929
- 7744
- 884
- 116
- 10
- 25
- 484
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