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 = 4 and y = 3.
- 2.Find the value of x² + 2xy + y² when x = 10 and y = 7.
- 3.Find the value of x² − y² when x = 8 and y = 4.
- 4.Use (a + b)² = a² + 2ab + b² to find 93².
- 5.Use (a − b)² = a² − 2ab + b² to find 97².
- 6.If a + b = 5 and ab = 6, what is a² + b²?
- 7.Use (a − b)² = a² − 2ab + b² to find 26².
- 8.Find the value of x² + 2xy + y² when x = 13 and y = 7.
- 9.Use (a + b)² = a² + 2ab + b² to find 19².
- 10.Find the value of x² − y² when x = 15 and y = 1.
- 11.Use (a − b)² = a² − 2ab + b² to find 58².
- 12.Find the value of x² + 2xy + y² when x = 4 and y = 2.
- 13.Use (a − b)² = a² − 2ab + b² to find 27².
- 14.Use (a − b)² = a² − 2ab + b² to find 68².
- 15.If a + b = 10 and ab = 24, what is a² + b²?
- 16.Use a² − b² = (a + b)(a − b) to find 27² − 16².
- 17.Find the value of x² − 2xy + y² when x = 9 and y = 6.
- 18.Find the value of x² + 2xy + y² when x = 14 and y = 1.
- 19.Use a² − b² = (a + b)(a − b) to find 47² − 15².
- 20.Use (a + b)(a − b) = a² − b² to find 105 × 95.
- 21.Use (a − b)² = a² − 2ab + b² to find 35².
- 22.Use (a + b)(a − b) = a² − b² to find 64 × 56.
- 23.Use (a + b)² = a² + 2ab + b² to find 59².
- 24.Use (a − b)² = a² − 2ab + b² to find 81².
- 25.Use (a + b)(a − b) = a² − b² to find 92 × 88.
- 26.Use (a + b)² = a² + 2ab + b² to find 38².
- 27.Use (a + b)² = a² + 2ab + b² to find 72².
- 28.Use (a + b)(a − b) = a² − b² to find 93 × 87.
- 29.If a − b = 8 and ab = 9, what is a² + b²?
- 30.Find the value of x² − y² when x = 13 and y = 7.
- 31.Use (a + b)² = a² + 2ab + b² to find 92².
- 32.Use (a + b)² = a² + 2ab + b² to find 32².
- 33.Use (a + b)(a − b) = a² − b² to find 43 × 37.
- 34.Use (a + b)(a − b) = a² − b² to find 37 × 23.
- 35.Find the value of x² − 2xy + y² when x = 13 and y = 6.
- 36.Use (a − b)² = a² − 2ab + b² to find 39².
- 37.Use a² − b² = (a + b)(a − b) to find 33² − 14².
- 38.Use (a + b)(a − b) = a² − b² to find 39 × 21.
- 39.Use (a + b)(a − b) = a² − b² to find 72 × 68.
- 40.Use (a − b)² = a² − 2ab + b² to find 31².
Answer key
- 7
- 289
- 48
- 8649
- 9409
- 13
- 676
- 400
- 361
- 224
- 3364
- 36
- 729
- 4624
- 52
- 473
- 9
- 225
- 1984
- 9975
- 1225
- 3584
- 3481
- 6561
- 8096
- 1444
- 5184
- 8091
- 82
- 120
- 8464
- 1024
- 1591
- 851
- 49
- 1521
- 893
- 819
- 4896
- 961
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