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 31².
- 2.Use (a + b)(a − b) = a² − b² to find 87 × 73.
- 3.Find the value of x² − y² when x = 14 and y = 11.
- 4.Use (a + b)(a − b) = a² − b² to find 83 × 77.
- 5.Use (a + b)(a − b) = a² − b² to find 106 × 94.
- 6.Use a² − b² = (a + b)(a − b) to find 89² − 6².
- 7.Use (a + b)² = a² + 2ab + b² to find 96².
- 8.Use a² − b² = (a + b)(a − b) to find 24² − 15².
- 9.Use (a + b)² = a² + 2ab + b² to find 64².
- 10.Use (a + b)(a − b) = a² − b² to find 22 × 18.
- 11.If a + b = 14 and ab = 33, what is a² + b²?
- 12.If a + b = 13 and ab = 42, what is a² + b²?
- 13.If a − b = 2 and ab = 15, what is a² + b²?
- 14.Use (a + b)(a − b) = a² − b² to find 102 × 98.
- 15.Use a² − b² = (a + b)(a − b) to find 60² − 28².
- 16.Use (a − b)² = a² − 2ab + b² to find 11².
- 17.Find the value of x² − 2xy + y² when x = 12 and y = 11.
- 18.Use (a − b)² = a² − 2ab + b² to find 36².
- 19.Use (a + b)(a − b) = a² − b² to find 56 × 44.
- 20.Find the value of x² − 2xy + y² when x = 4 and y = 1.
- 21.Use (a + b)(a − b) = a² − b² to find 73 × 67.
- 22.Use a² − b² = (a + b)(a − b) to find 20² − 18².
- 23.If a − b = 1 and ab = 20, what is a² + b²?
- 24.If a − b = 2 and ab = 35, what is a² + b²?
- 25.If a + b = 10 and ab = 9, what is a² + b²?
- 26.Use (a + b)² = a² + 2ab + b² to find 35².
- 27.Find the value of x² + 2xy + y² when x = 9 and y = 8.
- 28.Use a² − b² = (a + b)(a − b) to find 65² − 7².
- 29.Use (a + b)² = a² + 2ab + b² to find 92².
- 30.Find the value of x² − 2xy + y² when x = 14 and y = 3.
- 31.Use (a + b)(a − b) = a² − b² to find 99 × 81.
- 32.Find the value of x² + 2xy + y² when x = 12 and y = 7.
- 33.Use (a + b)² = a² + 2ab + b² to find 85².
- 34.Use a² − b² = (a + b)(a − b) to find 43² − 38².
- 35.Use (a − b)² = a² − 2ab + b² to find 76².
- 36.Use a² − b² = (a + b)(a − b) to find 48² − 46².
- 37.If a + b = 5 and ab = 6, what is a² + b²?
- 38.Use (a − b)² = a² − 2ab + b² to find 99².
- 39.Use (a − b)² = a² − 2ab + b² to find 43².
- 40.Find the value of x² + 2xy + y² when x = 15 and y = 13.
Answer key
- 961
- 6351
- 75
- 6391
- 9964
- 7885
- 9216
- 351
- 4096
- 396
- 130
- 85
- 34
- 9996
- 2816
- 121
- 1
- 1296
- 2464
- 9
- 4891
- 76
- 41
- 74
- 82
- 1225
- 289
- 4176
- 8464
- 121
- 8019
- 361
- 7225
- 405
- 5776
- 188
- 13
- 9801
- 1849
- 784
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