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 = 7 and y = 3.
- 2.Find the value of x² + 2xy + y² when x = 12 and y = 11.
- 3.Find the value of x² + 2xy + y² when x = 9 and y = 8.
- 4.Use (a + b)(a − b) = a² − b² to find 53 × 47.
- 5.If a + b = 7 and ab = 12, what is a² + b²?
- 6.Find the value of x² − 2xy + y² when x = 5 and y = 2.
- 7.Use (a − b)² = a² − 2ab + b² to find 19².
- 8.Use (a − b)² = a² − 2ab + b² to find 23².
- 9.Use (a + b)² = a² + 2ab + b² to find 57².
- 10.If a + b = 11 and ab = 18, what is a² + b²?
- 11.If a + b = 21 and ab = 110, what is a² + b²?
- 12.Use (a + b)(a − b) = a² − b² to find 58 × 42.
- 13.Use (a + b)(a − b) = a² − b² to find 83 × 77.
- 14.Use (a + b)² = a² + 2ab + b² to find 59².
- 15.If a + b = 11 and ab = 24, what is a² + b²?
- 16.Use (a + b)² = a² + 2ab + b² to find 18².
- 17.Use (a + b)² = a² + 2ab + b² to find 73².
- 18.Use (a + b)(a − b) = a² − b² to find 47 × 33.
- 19.If a + b = 4 and ab = 3, what is a² + b²?
- 20.Find the value of x² + 2xy + y² when x = 4 and y = 1.
- 21.Use a² − b² = (a + b)(a − b) to find 63² − 22².
- 22.Use (a + b)² = a² + 2ab + b² to find 78².
- 23.Use (a − b)² = a² − 2ab + b² to find 18².
- 24.Use (a + b)² = a² + 2ab + b² to find 79².
- 25.Use (a + b)² = a² + 2ab + b² to find 56².
- 26.Find the value of x² + 2xy + y² when x = 10 and y = 3.
- 27.Use (a − b)² = a² − 2ab + b² to find 24².
- 28.Find the value of x² − y² when x = 9 and y = 2.
- 29.If a + b = 5 and ab = 6, what is a² + b²?
- 30.Use (a + b)(a − b) = a² − b² to find 34 × 26.
- 31.Use a² − b² = (a + b)(a − b) to find 35² − 24².
- 32.If a − b = 2 and ab = 63, what is a² + b²?
- 33.If a + b = 8 and ab = 12, what is a² + b²?
- 34.Use (a + b)(a − b) = a² − b² to find 82 × 78.
- 35.Find the value of x² + 2xy + y² when x = 4 and y = 3.
- 36.Use a² − b² = (a + b)(a − b) to find 72² − 53².
- 37.Find the value of x² − 2xy + y² when x = 4 and y = 1.
- 38.Find the value of x² + 2xy + y² when x = 11 and y = 7.
- 39.Find the value of x² + 2xy + y² when x = 11 and y = 4.
- 40.Use (a + b)(a − b) = a² − b² to find 46 × 34.
Answer key
- 40
- 529
- 289
- 2491
- 25
- 9
- 361
- 529
- 3249
- 85
- 221
- 2436
- 6391
- 3481
- 73
- 324
- 5329
- 1551
- 10
- 25
- 3485
- 6084
- 324
- 6241
- 3136
- 169
- 576
- 77
- 13
- 884
- 649
- 130
- 40
- 6396
- 49
- 2375
- 9
- 324
- 225
- 1564
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