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)(a − b) = a² − b² to find 103 × 97.
- 2.Use (a − b)² = a² − 2ab + b² to find 19².
- 3.Find the value of x² − 2xy + y² when x = 8 and y = 2.
- 4.Use (a + b)² = a² + 2ab + b² to find 61².
- 5.Find the value of x² − 2xy + y² when x = 10 and y = 3.
- 6.Use a² − b² = (a + b)(a − b) to find 78² − 16².
- 7.Find the value of x² − y² when x = 11 and y = 1.
- 8.Find the value of x² + 2xy + y² when x = 8 and y = 1.
- 9.Use (a + b)² = a² + 2ab + b² to find 21².
- 10.If a − b = 3 and ab = 10, what is a² + b²?
- 11.Use (a + b)² = a² + 2ab + b² to find 12².
- 12.Use (a + b)² = a² + 2ab + b² to find 26².
- 13.Use (a + b)² = a² + 2ab + b² to find 22².
- 14.Find the value of x² − 2xy + y² when x = 12 and y = 6.
- 15.Use (a + b)² = a² + 2ab + b² to find 81².
- 16.Use a² − b² = (a + b)(a − b) to find 73² − 30².
- 17.Use (a + b)(a − b) = a² − b² to find 107 × 93.
- 18.Find the value of x² − y² when x = 8 and y = 2.
- 19.Use (a − b)² = a² − 2ab + b² to find 55².
- 20.Use a² − b² = (a + b)(a − b) to find 52² − 5².
- 21.Use (a + b)(a − b) = a² − b² to find 57 × 43.
- 22.Use a² − b² = (a + b)(a − b) to find 64² − 49².
- 23.Use (a + b)² = a² + 2ab + b² to find 42².
- 24.If a − b = 4 and ab = 96, what is a² + b²?
- 25.Find the value of x² + 2xy + y² when x = 7 and y = 2.
- 26.Find the value of x² + 2xy + y² when x = 4 and y = 2.
- 27.Find the value of x² + 2xy + y² when x = 7 and y = 4.
- 28.Use a² − b² = (a + b)(a − b) to find 37² − 3².
- 29.Use a² − b² = (a + b)(a − b) to find 30² − 15².
- 30.Use (a − b)² = a² − 2ab + b² to find 34².
- 31.Use (a + b)(a − b) = a² − b² to find 34 × 26.
- 32.Use (a + b)² = a² + 2ab + b² to find 45².
- 33.Use a² − b² = (a + b)(a − b) to find 70² − 63².
- 34.Use (a + b)² = a² + 2ab + b² to find 38².
- 35.Use (a + b)² = a² + 2ab + b² to find 24².
- 36.Use (a − b)² = a² − 2ab + b² to find 42².
- 37.Use (a + b)(a − b) = a² − b² to find 46 × 34.
- 38.Use (a + b)(a − b) = a² − b² to find 84 × 76.
- 39.Find the value of x² − 2xy + y² when x = 6 and y = 4.
- 40.Use (a + b)(a − b) = a² − b² to find 35 × 25.
Answer key
- 9991
- 361
- 36
- 3721
- 49
- 5828
- 120
- 81
- 441
- 29
- 144
- 676
- 484
- 36
- 6561
- 4429
- 9951
- 60
- 3025
- 2679
- 2451
- 1695
- 1764
- 208
- 81
- 36
- 121
- 1360
- 675
- 1156
- 884
- 2025
- 931
- 1444
- 576
- 1764
- 1564
- 6384
- 4
- 875
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