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 13².
- 2.If a + b = 4 and ab = 3, what is a² + b²?
- 3.Use (a − b)² = a² − 2ab + b² to find 39².
- 4.Use a² − b² = (a + b)(a − b) to find 78² − 52².
- 5.Use (a + b)² = a² + 2ab + b² to find 26².
- 6.Find the value of x² + 2xy + y² when x = 7 and y = 4.
- 7.If a + b = 18 and ab = 80, what is a² + b²?
- 8.Use (a + b)(a − b) = a² − b² to find 36 × 24.
- 9.Find the value of x² + 2xy + y² when x = 10 and y = 9.
- 10.If a + b = 8 and ab = 12, what is a² + b²?
- 11.Use a² − b² = (a + b)(a − b) to find 45² − 2².
- 12.Use (a + b)² = a² + 2ab + b² to find 92².
- 13.Use a² − b² = (a + b)(a − b) to find 28² − 14².
- 14.Use (a − b)² = a² − 2ab + b² to find 31².
- 15.Find the value of x² − y² when x = 4 and y = 2.
- 16.Use (a − b)² = a² − 2ab + b² to find 49².
- 17.Use (a + b)² = a² + 2ab + b² to find 103².
- 18.Use a² − b² = (a + b)(a − b) to find 57² − 46².
- 19.If a − b = 1 and ab = 132, what is a² + b²?
- 20.Use (a + b)² = a² + 2ab + b² to find 105².
- 21.Use (a + b)² = a² + 2ab + b² to find 58².
- 22.Find the value of x² − y² when x = 14 and y = 7.
- 23.Use a² − b² = (a + b)(a − b) to find 43² − 3².
- 24.Use a² − b² = (a + b)(a − b) to find 64² − 42².
- 25.Use (a + b)² = a² + 2ab + b² to find 49².
- 26.Use (a + b)² = a² + 2ab + b² to find 11².
- 27.If a − b = 1 and ab = 6, what is a² + b²?
- 28.Use (a + b)² = a² + 2ab + b² to find 13².
- 29.Find the value of x² − y² when x = 15 and y = 4.
- 30.Use (a + b)² = a² + 2ab + b² to find 32².
- 31.Use (a − b)² = a² − 2ab + b² to find 77².
- 32.Use (a + b)² = a² + 2ab + b² to find 24².
- 33.Use (a − b)² = a² − 2ab + b² to find 16².
- 34.If a − b = 6 and ab = 27, what is a² + b²?
- 35.Find the value of x² + 2xy + y² when x = 11 and y = 5.
- 36.Use a² − b² = (a + b)(a − b) to find 28² − 23².
- 37.Use (a − b)² = a² − 2ab + b² to find 76².
- 38.If a + b = 14 and ab = 48, what is a² + b²?
- 39.Use (a − b)² = a² − 2ab + b² to find 48².
- 40.Find the value of x² + 2xy + y² when x = 11 and y = 1.
Answer key
- 169
- 10
- 1521
- 3380
- 676
- 121
- 164
- 864
- 361
- 40
- 2021
- 8464
- 588
- 961
- 12
- 2401
- 10609
- 1133
- 265
- 11025
- 3364
- 147
- 1840
- 2332
- 2401
- 121
- 13
- 169
- 209
- 1024
- 5929
- 576
- 256
- 90
- 256
- 255
- 5776
- 100
- 2304
- 144
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