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 49².
- 2.Use a² − b² = (a + b)(a − b) to find 20² − 1².
- 3.Find the value of x² + 2xy + y² when x = 10 and y = 1.
- 4.Use a² − b² = (a + b)(a − b) to find 96² − 1².
- 5.Use (a + b)(a − b) = a² − b² to find 98 × 82.
- 6.Use (a + b)² = a² + 2ab + b² to find 95².
- 7.Use (a + b)² = a² + 2ab + b² to find 93².
- 8.If a + b = 6 and ab = 5, what is a² + b²?
- 9.Use a² − b² = (a + b)(a − b) to find 91² − 48².
- 10.Use a² − b² = (a + b)(a − b) to find 85² − 7².
- 11.Use (a + b)² = a² + 2ab + b² to find 19².
- 12.Use (a + b)(a − b) = a² − b² to find 36 × 24.
- 13.Use (a + b)² = a² + 2ab + b² to find 106².
- 14.If a + b = 15 and ab = 36, what is a² + b²?
- 15.Use (a + b)(a − b) = a² − b² to find 63 × 57.
- 16.Use (a − b)² = a² − 2ab + b² to find 97².
- 17.Use (a + b)² = a² + 2ab + b² to find 26².
- 18.Use (a + b)² = a² + 2ab + b² to find 13².
- 19.Use a² − b² = (a + b)(a − b) to find 95² − 77².
- 20.Use (a + b)² = a² + 2ab + b² to find 101².
- 21.If a − b = 2 and ab = 15, what is a² + b²?
- 22.Find the value of x² − y² when x = 5 and y = 1.
- 23.Use a² − b² = (a + b)(a − b) to find 97² − 69².
- 24.Use (a − b)² = a² − 2ab + b² to find 52².
- 25.Use a² − b² = (a + b)(a − b) to find 47² − 32².
- 26.If a − b = 10 and ab = 11, what is a² + b²?
- 27.Find the value of x² + 2xy + y² when x = 3 and y = 1.
- 28.Find the value of x² + 2xy + y² when x = 12 and y = 1.
- 29.Use a² − b² = (a + b)(a − b) to find 40² − 15².
- 30.Use (a + b)² = a² + 2ab + b² to find 84².
- 31.Find the value of x² + 2xy + y² when x = 4 and y = 1.
- 32.Use (a − b)² = a² − 2ab + b² to find 16².
- 33.Use (a − b)² = a² − 2ab + b² to find 35².
- 34.Use (a + b)² = a² + 2ab + b² to find 11².
- 35.Use (a + b)(a − b) = a² − b² to find 49 × 31.
- 36.Find the value of x² − 2xy + y² when x = 9 and y = 2.
- 37.If a − b = 8 and ab = 9, what is a² + b²?
- 38.Find the value of x² + 2xy + y² when x = 13 and y = 8.
- 39.Use a² − b² = (a + b)(a − b) to find 95² − 4².
- 40.Use (a − b)² = a² − 2ab + b² to find 23².
Answer key
- 2401
- 399
- 121
- 9215
- 8036
- 9025
- 8649
- 26
- 5977
- 7176
- 361
- 864
- 11236
- 153
- 3591
- 9409
- 676
- 169
- 3096
- 10201
- 34
- 24
- 4648
- 2704
- 1185
- 122
- 16
- 169
- 1375
- 7056
- 25
- 256
- 1225
- 121
- 1519
- 49
- 82
- 441
- 9009
- 529
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