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 − y² when x = 11 and y = 7.
- 2.Use (a − b)² = a² − 2ab + b² to find 75².
- 3.Use (a + b)(a − b) = a² − b² to find 66 × 54.
- 4.Use (a + b)(a − b) = a² − b² to find 107 × 93.
- 5.Use (a − b)² = a² − 2ab + b² to find 49².
- 6.If a − b = 5 and ab = 24, what is a² + b²?
- 7.Use (a + b)(a − b) = a² − b² to find 57 × 43.
- 8.If a − b = 2 and ab = 3, what is a² + b²?
- 9.Use (a + b)² = a² + 2ab + b² to find 95².
- 10.If a − b = 1 and ab = 2, what is a² + b²?
- 11.If a − b = 5 and ab = 14, what is a² + b²?
- 12.Use (a − b)² = a² − 2ab + b² to find 17².
- 13.Find the value of x² + 2xy + y² when x = 6 and y = 4.
- 14.Use (a + b)(a − b) = a² − b² to find 28 × 12.
- 15.If a − b = 3 and ab = 54, what is a² + b²?
- 16.Use (a + b)(a − b) = a² − b² to find 55 × 45.
- 17.Use (a + b)² = a² + 2ab + b² to find 89².
- 18.Use (a + b)² = a² + 2ab + b² to find 34².
- 19.Use a² − b² = (a + b)(a − b) to find 78² − 1².
- 20.Use (a + b)² = a² + 2ab + b² to find 57².
- 21.If a − b = 3 and ab = 18, what is a² + b²?
- 22.If a − b = 10 and ab = 24, what is a² + b²?
- 23.Find the value of x² + 2xy + y² when x = 15 and y = 11.
- 24.Find the value of x² − 2xy + y² when x = 5 and y = 2.
- 25.Use (a + b)² = a² + 2ab + b² to find 32².
- 26.Find the value of x² + 2xy + y² when x = 12 and y = 4.
- 27.If a − b = 2 and ab = 8, what is a² + b²?
- 28.Use (a − b)² = a² − 2ab + b² to find 39².
- 29.Use a² − b² = (a + b)(a − b) to find 27² − 11².
- 30.Use a² − b² = (a + b)(a − b) to find 27² − 5².
- 31.Use (a + b)(a − b) = a² − b² to find 71 × 69.
- 32.Use (a + b)² = a² + 2ab + b² to find 49².
- 33.Use (a − b)² = a² − 2ab + b² to find 54².
- 34.Find the value of x² − 2xy + y² when x = 14 and y = 12.
- 35.Use (a + b)² = a² + 2ab + b² to find 101².
- 36.Use a² − b² = (a + b)(a − b) to find 91² − 8².
- 37.Find the value of x² − 2xy + y² when x = 3 and y = 2.
- 38.Find the value of x² + 2xy + y² when x = 3 and y = 1.
- 39.Use (a + b)² = a² + 2ab + b² to find 55².
- 40.Use a² − b² = (a + b)(a − b) to find 59² − 18².
Answer key
- 72
- 5625
- 3564
- 9951
- 2401
- 73
- 2451
- 10
- 9025
- 5
- 53
- 289
- 100
- 336
- 117
- 2475
- 7921
- 1156
- 6083
- 3249
- 45
- 148
- 676
- 9
- 1024
- 256
- 20
- 1521
- 608
- 704
- 4899
- 2401
- 2916
- 4
- 10201
- 8217
- 1
- 16
- 3025
- 3157
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