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.
NameDateTime takenScore ___ / 40
- 1.Use (a + b)² = a² + 2ab + b² to find 102².
- 2.If a + b = 3 and ab = 2, what is a² + b²?
- 3.Use (a + b)(a − b) = a² − b² to find 76 × 64.
- 4.Use (a + b)² = a² + 2ab + b² to find 28².
- 5.Use (a − b)² = a² − 2ab + b² to find 57².
- 6.Use (a + b)(a − b) = a² − b² to find 106 × 94.
- 7.Find the value of x² + 2xy + y² when x = 6 and y = 2.
- 8.Use (a + b)(a − b) = a² − b² to find 46 × 34.
- 9.Use (a + b)(a − b) = a² − b² to find 66 × 54.
- 10.Find the value of x² − y² when x = 6 and y = 2.
- 11.Use (a − b)² = a² − 2ab + b² to find 76².
- 12.Use (a + b)² = a² + 2ab + b² to find 37².
- 13.Use (a + b)² = a² + 2ab + b² to find 85².
- 14.If a + b = 7 and ab = 10, what is a² + b²?
- 15.Use (a − b)² = a² − 2ab + b² to find 18².
- 16.Use a² − b² = (a + b)(a − b) to find 32² − 7².
- 17.Find the value of x² − 2xy + y² when x = 4 and y = 2.
- 18.Use (a + b)(a − b) = a² − b² to find 22 × 18.
- 19.Use (a − b)² = a² − 2ab + b² to find 88².
- 20.Use (a − b)² = a² − 2ab + b² to find 22².
- 21.Use (a + b)(a − b) = a² − b² to find 21 × 19.
- 22.If a − b = 5 and ab = 6, what is a² + b²?
- 23.Use (a − b)² = a² − 2ab + b² to find 43².
- 24.If a + b = 17 and ab = 70, what is a² + b²?
- 25.Use (a − b)² = a² − 2ab + b² to find 36².
- 26.Use a² − b² = (a + b)(a − b) to find 25² − 10².
- 27.Use (a − b)² = a² − 2ab + b² to find 66².
- 28.Use (a − b)² = a² − 2ab + b² to find 12².
- 29.Use (a + b)(a − b) = a² − b² to find 82 × 78.
- 30.Use (a − b)² = a² − 2ab + b² to find 68².
- 31.Use (a + b)(a − b) = a² − b² to find 55 × 45.
- 32.Use a² − b² = (a + b)(a − b) to find 33² − 10².
- 33.Use (a − b)² = a² − 2ab + b² to find 99².
- 34.Use (a + b)(a − b) = a² − b² to find 95 × 85.
- 35.Use (a + b)² = a² + 2ab + b² to find 81².
- 36.If a − b = 1 and ab = 6, what is a² + b²?
- 37.Use (a + b)² = a² + 2ab + b² to find 49².
- 38.Find the value of x² − y² when x = 6 and y = 1.
- 39.Use (a + b)² = a² + 2ab + b² to find 88².
- 40.Find the value of x² + 2xy + y² when x = 6 and y = 4.
Answer key
- 10404
- 5
- 4864
- 784
- 3249
- 9964
- 64
- 1564
- 3564
- 32
- 5776
- 1369
- 7225
- 29
- 324
- 975
- 4
- 396
- 7744
- 484
- 399
- 37
- 1849
- 149
- 1296
- 525
- 4356
- 144
- 6396
- 4624
- 2475
- 989
- 9801
- 8075
- 6561
- 13
- 2401
- 35
- 7744
- 100
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