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 64².
- 2.Use (a + b)² = a² + 2ab + b² to find 36².
- 3.Use (a + b)(a − b) = a² − b² to find 103 × 97.
- 4.Use (a − b)² = a² − 2ab + b² to find 23².
- 5.Find the value of x² − 2xy + y² when x = 5 and y = 3.
- 6.If a − b = 1 and ab = 6, what is a² + b²?
- 7.Use (a + b)(a − b) = a² − b² to find 42 × 38.
- 8.Use (a + b)(a − b) = a² − b² to find 104 × 96.
- 9.Use (a + b)² = a² + 2ab + b² to find 43².
- 10.Use a² − b² = (a + b)(a − b) to find 56² − 26².
- 11.Use (a + b)(a − b) = a² − b² to find 81 × 79.
- 12.Use (a + b)(a − b) = a² − b² to find 72 × 68.
- 13.Use (a + b)² = a² + 2ab + b² to find 56².
- 14.Use (a − b)² = a² − 2ab + b² to find 42².
- 15.Use (a + b)² = a² + 2ab + b² to find 85².
- 16.Use a² − b² = (a + b)(a − b) to find 95² − 30².
- 17.Use (a − b)² = a² − 2ab + b² to find 26².
- 18.Use (a + b)(a − b) = a² − b² to find 46 × 34.
- 19.Use (a + b)(a − b) = a² − b² to find 95 × 85.
- 20.Use (a − b)² = a² − 2ab + b² to find 71².
- 21.Use a² − b² = (a + b)(a − b) to find 29² − 2².
- 22.Use a² − b² = (a + b)(a − b) to find 22² − 3².
- 23.Use a² − b² = (a + b)(a − b) to find 63² − 13².
- 24.If a + b = 4 and ab = 3, what is a² + b²?
- 25.Use (a − b)² = a² − 2ab + b² to find 69².
- 26.Use (a + b)² = a² + 2ab + b² to find 18².
- 27.Use a² − b² = (a + b)(a − b) to find 97² − 60².
- 28.Use a² − b² = (a + b)(a − b) to find 80² − 73².
- 29.Use a² − b² = (a + b)(a − b) to find 69² − 19².
- 30.Use (a − b)² = a² − 2ab + b² to find 41².
- 31.Use (a − b)² = a² − 2ab + b² to find 83².
- 32.Use (a + b)(a − b) = a² − b² to find 85 × 75.
- 33.Use (a + b)(a − b) = a² − b² to find 45 × 35.
- 34.If a − b = 4 and ab = 5, what is a² + b²?
- 35.Use (a + b)² = a² + 2ab + b² to find 52².
- 36.Find the value of x² − y² when x = 5 and y = 2.
- 37.Use (a − b)² = a² − 2ab + b² to find 44².
- 38.Use (a − b)² = a² − 2ab + b² to find 87².
- 39.Use a² − b² = (a + b)(a − b) to find 31² − 12².
- 40.Use (a + b)² = a² + 2ab + b² to find 55².
Answer key
- 4096
- 1296
- 9991
- 529
- 4
- 13
- 1596
- 9984
- 1849
- 2460
- 6399
- 4896
- 3136
- 1764
- 7225
- 8125
- 676
- 1564
- 8075
- 5041
- 837
- 475
- 3800
- 10
- 4761
- 324
- 5809
- 1071
- 4400
- 1681
- 6889
- 6375
- 1575
- 26
- 2704
- 21
- 1936
- 7569
- 817
- 3025
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