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 77².
- 2.Use (a + b)² = a² + 2ab + b² to find 63².
- 3.Use a² − b² = (a + b)(a − b) to find 89² − 79².
- 4.Use (a − b)² = a² − 2ab + b² to find 89².
- 5.Use a² − b² = (a + b)(a − b) to find 65² − 33².
- 6.Use a² − b² = (a + b)(a − b) to find 67² − 26².
- 7.Use (a − b)² = a² − 2ab + b² to find 59².
- 8.If a − b = 10 and ab = 11, what is a² + b²?
- 9.Use a² − b² = (a + b)(a − b) to find 22² − 10².
- 10.Use (a + b)² = a² + 2ab + b² to find 17².
- 11.Use a² − b² = (a + b)(a − b) to find 62² − 46².
- 12.If a + b = 5 and ab = 6, what is a² + b²?
- 13.If a + b = 11 and ab = 30, what is a² + b²?
- 14.Use (a + b)² = a² + 2ab + b² to find 108².
- 15.Use (a + b)(a − b) = a² − b² to find 105 × 95.
- 16.If a + b = 3 and ab = 2, what is a² + b²?
- 17.Use a² − b² = (a + b)(a − b) to find 96² − 51².
- 18.Find the value of x² + 2xy + y² when x = 11 and y = 4.
- 19.Use (a + b)² = a² + 2ab + b² to find 43².
- 20.Use (a − b)² = a² − 2ab + b² to find 43².
- 21.Use (a + b)(a − b) = a² − b² to find 72 × 68.
- 22.Use (a + b)² = a² + 2ab + b² to find 34².
- 23.Find the value of x² − 2xy + y² when x = 7 and y = 6.
- 24.Use (a − b)² = a² − 2ab + b² to find 31².
- 25.Use a² − b² = (a + b)(a − b) to find 99² − 33².
- 26.Find the value of x² − 2xy + y² when x = 3 and y = 1.
- 27.Use (a − b)² = a² − 2ab + b² to find 26².
- 28.Use (a − b)² = a² − 2ab + b² to find 84².
- 29.Use (a + b)² = a² + 2ab + b² to find 65².
- 30.Use (a + b)(a − b) = a² − b² to find 44 × 36.
- 31.Use (a − b)² = a² − 2ab + b² to find 35².
- 32.Find the value of x² − 2xy + y² when x = 14 and y = 12.
- 33.If a + b = 8 and ab = 12, what is a² + b²?
- 34.Find the value of x² − 2xy + y² when x = 13 and y = 6.
- 35.Use (a − b)² = a² − 2ab + b² to find 83².
- 36.Use a² − b² = (a + b)(a − b) to find 47² − 16².
- 37.Use (a + b)² = a² + 2ab + b² to find 57².
- 38.Find the value of x² − 2xy + y² when x = 13 and y = 9.
- 39.If a + b = 20 and ab = 96, what is a² + b²?
- 40.If a + b = 21 and ab = 110, what is a² + b²?
Answer key
- 5929
- 3969
- 1680
- 7921
- 3136
- 3813
- 3481
- 122
- 384
- 289
- 1728
- 13
- 61
- 11664
- 9975
- 5
- 6615
- 225
- 1849
- 1849
- 4896
- 1156
- 1
- 961
- 8712
- 4
- 676
- 7056
- 4225
- 1584
- 1225
- 4
- 40
- 49
- 6889
- 1953
- 3249
- 16
- 208
- 221
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