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 93².
- 2.Find the value of x² + 2xy + y² when x = 14 and y = 8.
- 3.Use (a − b)² = a² − 2ab + b² to find 38².
- 4.If a − b = 5 and ab = 6, what is a² + b²?
- 5.Use (a + b)(a − b) = a² − b² to find 67 × 53.
- 6.If a − b = 2 and ab = 8, what is a² + b²?
- 7.Use (a + b)(a − b) = a² − b² to find 81 × 79.
- 8.If a + b = 8 and ab = 7, what is a² + b²?
- 9.Use (a + b)² = a² + 2ab + b² to find 86².
- 10.Find the value of x² + 2xy + y² when x = 14 and y = 6.
- 11.Use (a + b)(a − b) = a² − b² to find 77 × 63.
- 12.Use (a + b)(a − b) = a² − b² to find 22 × 18.
- 13.If a − b = 6 and ab = 72, what is a² + b²?
- 14.Find the value of x² − y² when x = 5 and y = 3.
- 15.Find the value of x² − 2xy + y² when x = 11 and y = 8.
- 16.Use (a + b)(a − b) = a² − b² to find 74 × 66.
- 17.Use (a + b)² = a² + 2ab + b² to find 99².
- 18.Use a² − b² = (a + b)(a − b) to find 98² − 20².
- 19.Use (a + b)² = a² + 2ab + b² to find 42².
- 20.Use a² − b² = (a + b)(a − b) to find 66² − 19².
- 21.If a + b = 15 and ab = 56, what is a² + b²?
- 22.If a + b = 13 and ab = 40, what is a² + b²?
- 23.Find the value of x² + 2xy + y² when x = 9 and y = 1.
- 24.Use (a + b)(a − b) = a² − b² to find 56 × 44.
- 25.Find the value of x² + 2xy + y² when x = 12 and y = 4.
- 26.Find the value of x² − 2xy + y² when x = 15 and y = 9.
- 27.Find the value of x² − y² when x = 5 and y = 1.
- 28.Find the value of x² + 2xy + y² when x = 3 and y = 2.
- 29.Use a² − b² = (a + b)(a − b) to find 73² − 41².
- 30.Use (a + b)(a − b) = a² − b² to find 39 × 21.
- 31.Use (a − b)² = a² − 2ab + b² to find 94².
- 32.Use a² − b² = (a + b)(a − b) to find 87² − 41².
- 33.Use (a + b)² = a² + 2ab + b² to find 17².
- 34.Find the value of x² − 2xy + y² when x = 12 and y = 10.
- 35.Use (a − b)² = a² − 2ab + b² to find 61².
- 36.Use a² − b² = (a + b)(a − b) to find 74² − 63².
- 37.If a + b = 5 and ab = 6, what is a² + b²?
- 38.Use (a − b)² = a² − 2ab + b² to find 76².
- 39.Use (a + b)(a − b) = a² − b² to find 86 × 74.
- 40.Use (a − b)² = a² − 2ab + b² to find 19².
Answer key
- 8649
- 484
- 1444
- 37
- 3551
- 20
- 6399
- 50
- 7396
- 400
- 4851
- 396
- 180
- 16
- 9
- 4884
- 9801
- 9204
- 1764
- 3995
- 113
- 89
- 100
- 2464
- 256
- 36
- 24
- 25
- 3648
- 819
- 8836
- 5888
- 289
- 4
- 3721
- 1507
- 13
- 5776
- 6364
- 361
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