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)(a − b) = a² − b² to find 107 × 93.
- 2.Use (a − b)² = a² − 2ab + b² to find 46².
- 3.Use (a − b)² = a² − 2ab + b² to find 36².
- 4.If a + b = 3 and ab = 2, what is a² + b²?
- 5.Use a² − b² = (a + b)(a − b) to find 21² − 11².
- 6.If a − b = 1 and ab = 2, what is a² + b²?
- 7.Use (a + b)² = a² + 2ab + b² to find 22².
- 8.Use (a + b)(a − b) = a² − b² to find 33 × 27.
- 9.Use (a + b)² = a² + 2ab + b² to find 52².
- 10.Use (a + b)² = a² + 2ab + b² to find 95².
- 11.Use a² − b² = (a + b)(a − b) to find 56² − 1².
- 12.Find the value of x² + 2xy + y² when x = 5 and y = 3.
- 13.Use a² − b² = (a + b)(a − b) to find 84² − 18².
- 14.Use (a + b)(a − b) = a² − b² to find 62 × 58.
- 15.Use (a − b)² = a² − 2ab + b² to find 32².
- 16.Use (a + b)(a − b) = a² − b² to find 37 × 23.
- 17.Use a² − b² = (a + b)(a − b) to find 86² − 33².
- 18.Use (a + b)(a − b) = a² − b² to find 101 × 99.
- 19.Find the value of x² − 2xy + y² when x = 4 and y = 3.
- 20.If a − b = 10 and ab = 11, what is a² + b²?
- 21.Find the value of x² − 2xy + y² when x = 11 and y = 4.
- 22.Use (a − b)² = a² − 2ab + b² to find 86².
- 23.Find the value of x² − y² when x = 10 and y = 5.
- 24.If a − b = 6 and ab = 27, what is a² + b²?
- 25.Use (a − b)² = a² − 2ab + b² to find 17².
- 26.Use a² − b² = (a + b)(a − b) to find 57² − 15².
- 27.Find the value of x² − y² when x = 12 and y = 5.
- 28.Find the value of x² − y² when x = 5 and y = 4.
- 29.If a + b = 8 and ab = 12, what is a² + b²?
- 30.Find the value of x² − y² when x = 4 and y = 3.
- 31.Use (a + b)(a − b) = a² − b² to find 31 × 29.
- 32.Use (a − b)² = a² − 2ab + b² to find 34².
- 33.Use (a + b)² = a² + 2ab + b² to find 104².
- 34.Use (a + b)² = a² + 2ab + b² to find 13².
- 35.Use (a − b)² = a² − 2ab + b² to find 71².
- 36.Find the value of x² − 2xy + y² when x = 10 and y = 3.
- 37.Use (a − b)² = a² − 2ab + b² to find 76².
- 38.Use (a − b)² = a² − 2ab + b² to find 98².
- 39.Use (a − b)² = a² − 2ab + b² to find 93².
- 40.Use (a + b)² = a² + 2ab + b² to find 14².
Answer key
- 9951
- 2116
- 1296
- 5
- 320
- 5
- 484
- 891
- 2704
- 9025
- 3135
- 64
- 6732
- 3596
- 1024
- 851
- 6307
- 9999
- 1
- 122
- 49
- 7396
- 75
- 90
- 289
- 3024
- 119
- 9
- 40
- 7
- 899
- 1156
- 10816
- 169
- 5041
- 49
- 5776
- 9604
- 8649
- 196
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