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 = 6 and y = 3.
- 2.Use a² − b² = (a + b)(a − b) to find 20² − 10².
- 3.Use (a + b)(a − b) = a² − b² to find 72 × 68.
- 4.Use (a + b)² = a² + 2ab + b² to find 22².
- 5.Use (a − b)² = a² − 2ab + b² to find 48².
- 6.Use a² − b² = (a + b)(a − b) to find 99² − 74².
- 7.If a + b = 5 and ab = 6, what is a² + b²?
- 8.Use (a + b)(a − b) = a² − b² to find 33 × 27.
- 9.Use (a + b)(a − b) = a² − b² to find 95 × 85.
- 10.Use (a + b)² = a² + 2ab + b² to find 102².
- 11.Find the value of x² − y² when x = 9 and y = 1.
- 12.If a + b = 12 and ab = 27, what is a² + b²?
- 13.Use (a + b)(a − b) = a² − b² to find 48 × 32.
- 14.Find the value of x² − y² when x = 9 and y = 5.
- 15.Use (a + b)² = a² + 2ab + b² to find 88².
- 16.If a − b = 2 and ab = 3, what is a² + b²?
- 17.Use (a − b)² = a² − 2ab + b² to find 29².
- 18.Use (a − b)² = a² − 2ab + b² to find 54².
- 19.Use a² − b² = (a + b)(a − b) to find 96² − 14².
- 20.Find the value of x² − y² when x = 7 and y = 5.
- 21.Use (a − b)² = a² − 2ab + b² to find 88².
- 22.If a − b = 6 and ab = 27, what is a² + b²?
- 23.Use a² − b² = (a + b)(a − b) to find 55² − 34².
- 24.Find the value of x² + 2xy + y² when x = 7 and y = 4.
- 25.Use (a − b)² = a² − 2ab + b² to find 31².
- 26.Use (a − b)² = a² − 2ab + b² to find 66².
- 27.Use (a + b)(a − b) = a² − b² to find 89 × 71.
- 28.If a + b = 5 and ab = 4, what is a² + b²?
- 29.Use (a − b)² = a² − 2ab + b² to find 79².
- 30.If a + b = 9 and ab = 18, what is a² + b²?
- 31.Use a² − b² = (a + b)(a − b) to find 35² − 24².
- 32.Use (a + b)² = a² + 2ab + b² to find 54².
- 33.If a − b = 4 and ab = 60, what is a² + b²?
- 34.Use a² − b² = (a + b)(a − b) to find 40² − 37².
- 35.Find the value of x² − y² when x = 8 and y = 5.
- 36.Use a² − b² = (a + b)(a − b) to find 81² − 17².
- 37.Use a² − b² = (a + b)(a − b) to find 37² − 25².
- 38.Use (a + b)(a − b) = a² − b² to find 31 × 29.
- 39.Find the value of x² − 2xy + y² when x = 10 and y = 3.
- 40.Find the value of x² − 2xy + y² when x = 3 and y = 2.
Answer key
- 27
- 300
- 4896
- 484
- 2304
- 4325
- 13
- 891
- 8075
- 10404
- 80
- 90
- 1536
- 56
- 7744
- 10
- 841
- 2916
- 9020
- 24
- 7744
- 90
- 1869
- 121
- 961
- 4356
- 6319
- 17
- 6241
- 45
- 649
- 2916
- 136
- 231
- 39
- 6272
- 744
- 899
- 49
- 1
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