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 − 2xy + y² when x = 10 and y = 8.
- 2.If a − b = 1 and ab = 30, what is a² + b²?
- 3.If a − b = 2 and ab = 80, what is a² + b²?
- 4.Use a² − b² = (a + b)(a − b) to find 63² − 5².
- 5.Use (a + b)² = a² + 2ab + b² to find 84².
- 6.Use (a − b)² = a² − 2ab + b² to find 32².
- 7.Find the value of x² + 2xy + y² when x = 9 and y = 7.
- 8.Use a² − b² = (a + b)(a − b) to find 91² − 25².
- 9.Use (a + b)(a − b) = a² − b² to find 93 × 87.
- 10.Use (a + b)² = a² + 2ab + b² to find 13².
- 11.Find the value of x² + 2xy + y² when x = 7 and y = 6.
- 12.Find the value of x² − y² when x = 12 and y = 11.
- 13.Use a² − b² = (a + b)(a − b) to find 32² − 15².
- 14.Use (a + b)(a − b) = a² − b² to find 24 × 16.
- 15.Find the value of x² − y² when x = 12 and y = 3.
- 16.If a + b = 9 and ab = 18, what is a² + b²?
- 17.If a − b = 7 and ab = 30, what is a² + b²?
- 18.Find the value of x² − 2xy + y² when x = 5 and y = 1.
- 19.Use (a − b)² = a² − 2ab + b² to find 39².
- 20.Find the value of x² + 2xy + y² when x = 13 and y = 3.
- 21.If a + b = 16 and ab = 63, what is a² + b²?
- 22.If a − b = 2 and ab = 3, what is a² + b²?
- 23.Use (a + b)² = a² + 2ab + b² to find 21².
- 24.Use (a + b)² = a² + 2ab + b² to find 12².
- 25.Use a² − b² = (a + b)(a − b) to find 52² − 46².
- 26.If a − b = 1 and ab = 132, what is a² + b²?
- 27.Find the value of x² + 2xy + y² when x = 5 and y = 3.
- 28.Find the value of x² + 2xy + y² when x = 3 and y = 1.
- 29.Use (a + b)² = a² + 2ab + b² to find 79².
- 30.Use (a + b)² = a² + 2ab + b² to find 32².
- 31.If a + b = 4 and ab = 3, what is a² + b²?
- 32.Find the value of x² − 2xy + y² when x = 8 and y = 4.
- 33.Use (a + b)(a − b) = a² − b² to find 63 × 57.
- 34.Use a² − b² = (a + b)(a − b) to find 73² − 29².
- 35.If a − b = 1 and ab = 72, what is a² + b²?
- 36.Use a² − b² = (a + b)(a − b) to find 27² − 9².
- 37.Use (a − b)² = a² − 2ab + b² to find 41².
- 38.Find the value of x² − y² when x = 5 and y = 4.
- 39.Use (a − b)² = a² − 2ab + b² to find 82².
- 40.Use (a + b)(a − b) = a² − b² to find 59 × 41.
Answer key
- 4
- 61
- 164
- 3944
- 7056
- 1024
- 256
- 7656
- 8091
- 169
- 169
- 23
- 799
- 384
- 135
- 45
- 109
- 16
- 1521
- 256
- 130
- 10
- 441
- 144
- 588
- 265
- 64
- 16
- 6241
- 1024
- 10
- 16
- 3591
- 4488
- 145
- 648
- 1681
- 9
- 6724
- 2419
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