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 84².
- 2.Use a² − b² = (a + b)(a − b) to find 68² − 53².
- 3.Use a² − b² = (a + b)(a − b) to find 56² − 12².
- 4.Use a² − b² = (a + b)(a − b) to find 64² − 1².
- 5.Use (a + b)² = a² + 2ab + b² to find 68².
- 6.Use (a + b)² = a² + 2ab + b² to find 86².
- 7.Use (a + b)² = a² + 2ab + b² to find 13².
- 8.Use a² − b² = (a + b)(a − b) to find 40² − 35².
- 9.Use (a + b)(a − b) = a² − b² to find 32 × 28.
- 10.Use (a + b)² = a² + 2ab + b² to find 103².
- 11.Use (a + b)² = a² + 2ab + b² to find 46².
- 12.Use a² − b² = (a + b)(a − b) to find 72² − 9².
- 13.Use (a + b)² = a² + 2ab + b² to find 41².
- 14.If a − b = 6 and ab = 55, what is a² + b²?
- 15.Use (a − b)² = a² − 2ab + b² to find 29².
- 16.If a + b = 6 and ab = 8, what is a² + b²?
- 17.Use (a − b)² = a² − 2ab + b² to find 31².
- 18.Find the value of x² + 2xy + y² when x = 7 and y = 1.
- 19.Use (a + b)(a − b) = a² − b² to find 69 × 51.
- 20.Use a² − b² = (a + b)(a − b) to find 59² − 19².
- 21.Find the value of x² − 2xy + y² when x = 11 and y = 8.
- 22.Use (a − b)² = a² − 2ab + b² to find 61².
- 23.Use (a + b)(a − b) = a² − b² to find 28 × 12.
- 24.If a + b = 6 and ab = 5, what is a² + b²?
- 25.Find the value of x² − y² when x = 12 and y = 8.
- 26.Find the value of x² − y² when x = 9 and y = 5.
- 27.If a − b = 4 and ab = 5, what is a² + b²?
- 28.Use (a − b)² = a² − 2ab + b² to find 65².
- 29.Use a² − b² = (a + b)(a − b) to find 64² − 12².
- 30.Use (a − b)² = a² − 2ab + b² to find 96².
- 31.If a + b = 3 and ab = 2, what is a² + b²?
- 32.Find the value of x² + 2xy + y² when x = 7 and y = 6.
- 33.Find the value of x² + 2xy + y² when x = 4 and y = 2.
- 34.Use (a − b)² = a² − 2ab + b² to find 66².
- 35.Use a² − b² = (a + b)(a − b) to find 47² − 45².
- 36.If a − b = 5 and ab = 6, what is a² + b²?
- 37.Use a² − b² = (a + b)(a − b) to find 65² − 28².
- 38.Use a² − b² = (a + b)(a − b) to find 67² − 53².
- 39.Use (a + b)² = a² + 2ab + b² to find 82².
- 40.If a + b = 11 and ab = 30, what is a² + b²?
Answer key
- 7056
- 1815
- 2992
- 4095
- 4624
- 7396
- 169
- 375
- 896
- 10609
- 2116
- 5103
- 1681
- 146
- 841
- 20
- 961
- 64
- 3519
- 3120
- 9
- 3721
- 336
- 26
- 80
- 56
- 26
- 4225
- 3952
- 9216
- 5
- 169
- 36
- 4356
- 184
- 37
- 3441
- 1680
- 6724
- 61
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