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 a² − b² = (a + b)(a − b) to find 42² − 35².
- 2.Use (a + b)² = a² + 2ab + b² to find 49².
- 3.Find the value of x² − y² when x = 4 and y = 1.
- 4.Use (a − b)² = a² − 2ab + b² to find 43².
- 5.Use (a + b)(a − b) = a² − b² to find 103 × 97.
- 6.Use (a − b)² = a² − 2ab + b² to find 54².
- 7.Find the value of x² + 2xy + y² when x = 9 and y = 3.
- 8.Use a² − b² = (a + b)(a − b) to find 35² − 32².
- 9.Find the value of x² + 2xy + y² when x = 13 and y = 1.
- 10.Use (a − b)² = a² − 2ab + b² to find 32².
- 11.Use (a − b)² = a² − 2ab + b² to find 98².
- 12.Use (a − b)² = a² − 2ab + b² to find 84².
- 13.If a + b = 5 and ab = 4, what is a² + b²?
- 14.Find the value of x² + 2xy + y² when x = 15 and y = 12.
- 15.If a + b = 3 and ab = 2, what is a² + b²?
- 16.Use (a + b)(a − b) = a² − b² to find 43 × 37.
- 17.Use (a + b)(a − b) = a² − b² to find 95 × 85.
- 18.If a − b = 3 and ab = 4, what is a² + b²?
- 19.Use (a − b)² = a² − 2ab + b² to find 94².
- 20.If a + b = 4 and ab = 3, what is a² + b²?
- 21.If a + b = 12 and ab = 35, what is a² + b²?
- 22.If a − b = 3 and ab = 10, what is a² + b²?
- 23.Use (a − b)² = a² − 2ab + b² to find 77².
- 24.Use (a − b)² = a² − 2ab + b² to find 85².
- 25.Use (a + b)(a − b) = a² − b² to find 52 × 48.
- 26.Use (a + b)(a − b) = a² − b² to find 33 × 27.
- 27.Use (a + b)(a − b) = a² − b² to find 24 × 16.
- 28.Use (a − b)² = a² − 2ab + b² to find 25².
- 29.Use a² − b² = (a + b)(a − b) to find 38² − 4².
- 30.Use (a − b)² = a² − 2ab + b² to find 21².
- 31.Use (a + b)² = a² + 2ab + b² to find 52².
- 32.Use (a + b)² = a² + 2ab + b² to find 38².
- 33.Find the value of x² − y² when x = 5 and y = 1.
- 34.Use a² − b² = (a + b)(a − b) to find 53² − 36².
- 35.If a + b = 15 and ab = 50, what is a² + b²?
- 36.Use (a − b)² = a² − 2ab + b² to find 26².
- 37.Use a² − b² = (a + b)(a − b) to find 23² − 22².
- 38.Find the value of x² − y² when x = 6 and y = 5.
- 39.Find the value of x² + 2xy + y² when x = 6 and y = 4.
- 40.Use (a + b)² = a² + 2ab + b² to find 92².
Answer key
- 539
- 2401
- 15
- 1849
- 9991
- 2916
- 144
- 201
- 196
- 1024
- 9604
- 7056
- 17
- 729
- 5
- 1591
- 8075
- 17
- 8836
- 10
- 74
- 29
- 5929
- 7225
- 2496
- 891
- 384
- 625
- 1428
- 441
- 2704
- 1444
- 24
- 1513
- 125
- 676
- 45
- 11
- 100
- 8464
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