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)(a − b) = a² − b² to find 24 × 16.
- 2.Use a² − b² = (a + b)(a − b) to find 27² − 4².
- 3.Use (a + b)² = a² + 2ab + b² to find 101².
- 4.Use (a + b)(a − b) = a² − b² to find 104 × 96.
- 5.Use a² − b² = (a + b)(a − b) to find 25² − 10².
- 6.Find the value of x² + 2xy + y² when x = 10 and y = 9.
- 7.Use (a + b)² = a² + 2ab + b² to find 62².
- 8.If a − b = 9 and ab = 36, what is a² + b²?
- 9.Use a² − b² = (a + b)(a − b) to find 29² − 23².
- 10.Use (a − b)² = a² − 2ab + b² to find 85².
- 11.Find the value of x² − y² when x = 12 and y = 5.
- 12.If a + b = 17 and ab = 70, what is a² + b²?
- 13.Use (a − b)² = a² − 2ab + b² to find 87².
- 14.Use (a + b)(a − b) = a² − b² to find 88 × 72.
- 15.Find the value of x² + 2xy + y² when x = 6 and y = 2.
- 16.Use (a + b)² = a² + 2ab + b² to find 35².
- 17.Use (a − b)² = a² − 2ab + b² to find 77².
- 18.Use a² − b² = (a + b)(a − b) to find 38² − 11².
- 19.Use (a − b)² = a² − 2ab + b² to find 13².
- 20.Find the value of x² − 2xy + y² when x = 4 and y = 1.
- 21.If a + b = 19 and ab = 90, what is a² + b²?
- 22.Use (a + b)² = a² + 2ab + b² to find 75².
- 23.Use a² − b² = (a + b)(a − b) to find 96² − 21².
- 24.Use (a + b)² = a² + 2ab + b² to find 61².
- 25.Use (a − b)² = a² − 2ab + b² to find 31².
- 26.If a − b = 1 and ab = 6, what is a² + b²?
- 27.Use (a + b)(a − b) = a² − b² to find 83 × 77.
- 28.Use (a − b)² = a² − 2ab + b² to find 66².
- 29.Find the value of x² − y² when x = 4 and y = 3.
- 30.If a − b = 1 and ab = 12, what is a² + b²?
- 31.Use (a + b)(a − b) = a² − b² to find 93 × 87.
- 32.Use (a + b)(a − b) = a² − b² to find 59 × 41.
- 33.Use (a − b)² = a² − 2ab + b² to find 73².
- 34.Use a² − b² = (a + b)(a − b) to find 27² − 3².
- 35.Use (a − b)² = a² − 2ab + b² to find 54².
- 36.Use (a − b)² = a² − 2ab + b² to find 58².
- 37.Use (a + b)(a − b) = a² − b² to find 74 × 66.
- 38.Use a² − b² = (a + b)(a − b) to find 62² − 44².
- 39.If a + b = 15 and ab = 54, what is a² + b²?
- 40.Use (a + b)² = a² + 2ab + b² to find 102².
Answer key
- 384
- 713
- 10201
- 9984
- 525
- 361
- 3844
- 153
- 312
- 7225
- 119
- 149
- 7569
- 6336
- 64
- 1225
- 5929
- 1323
- 169
- 9
- 181
- 5625
- 8775
- 3721
- 961
- 13
- 6391
- 4356
- 7
- 25
- 8091
- 2419
- 5329
- 720
- 2916
- 3364
- 4884
- 1908
- 117
- 10404
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