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.If a + b = 14 and ab = 48, what is a² + b²?
- 2.If a + b = 8 and ab = 7, what is a² + b²?
- 3.Use (a + b)(a − b) = a² − b² to find 103 × 97.
- 4.Find the value of x² + 2xy + y² when x = 10 and y = 3.
- 5.Use (a + b)(a − b) = a² − b² to find 29 × 11.
- 6.Use a² − b² = (a + b)(a − b) to find 83² − 19².
- 7.Use (a + b)² = a² + 2ab + b² to find 42².
- 8.Use (a − b)² = a² − 2ab + b² to find 65².
- 9.Find the value of x² + 2xy + y² when x = 7 and y = 5.
- 10.Use (a + b)² = a² + 2ab + b² to find 69².
- 11.Use (a + b)² = a² + 2ab + b² to find 104².
- 12.Find the value of x² + 2xy + y² when x = 13 and y = 11.
- 13.Use (a − b)² = a² − 2ab + b² to find 62².
- 14.Use (a + b)² = a² + 2ab + b² to find 103².
- 15.Use (a − b)² = a² − 2ab + b² to find 77².
- 16.Use (a + b)² = a² + 2ab + b² to find 56².
- 17.Use (a + b)² = a² + 2ab + b² to find 12².
- 18.Use a² − b² = (a + b)(a − b) to find 59² − 54².
- 19.If a + b = 12 and ab = 35, what is a² + b²?
- 20.Use a² − b² = (a + b)(a − b) to find 23² − 5².
- 21.Use a² − b² = (a + b)(a − b) to find 73² − 15².
- 22.Use (a − b)² = a² − 2ab + b² to find 54².
- 23.Use (a − b)² = a² − 2ab + b² to find 99².
- 24.Use (a + b)(a − b) = a² − b² to find 28 × 12.
- 25.Use (a + b)² = a² + 2ab + b² to find 46².
- 26.Use a² − b² = (a + b)(a − b) to find 82² − 37².
- 27.If a − b = 1 and ab = 2, what is a² + b²?
- 28.If a + b = 8 and ab = 12, what is a² + b²?
- 29.If a − b = 7 and ab = 18, what is a² + b²?
- 30.Use (a + b)(a − b) = a² − b² to find 83 × 77.
- 31.Use a² − b² = (a + b)(a − b) to find 26² − 2².
- 32.Find the value of x² + 2xy + y² when x = 3 and y = 2.
- 33.Use (a − b)² = a² − 2ab + b² to find 32².
- 34.Use a² − b² = (a + b)(a − b) to find 48² − 33².
- 35.Use (a + b)² = a² + 2ab + b² to find 16².
- 36.Use (a + b)(a − b) = a² − b² to find 106 × 94.
- 37.Use (a + b)² = a² + 2ab + b² to find 55².
- 38.Use a² − b² = (a + b)(a − b) to find 49² − 5².
- 39.Find the value of x² + 2xy + y² when x = 13 and y = 2.
- 40.Find the value of x² − y² when x = 4 and y = 2.
Answer key
- 100
- 50
- 9991
- 169
- 319
- 6528
- 1764
- 4225
- 144
- 4761
- 10816
- 576
- 3844
- 10609
- 5929
- 3136
- 144
- 565
- 74
- 504
- 5104
- 2916
- 9801
- 336
- 2116
- 5355
- 5
- 40
- 85
- 6391
- 672
- 25
- 1024
- 1215
- 256
- 9964
- 3025
- 2376
- 225
- 12
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