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 = 19 and ab = 84, what is a² + b²?
- 2.Find the value of x² − 2xy + y² when x = 6 and y = 1.
- 3.Use a² − b² = (a + b)(a − b) to find 24² − 17².
- 4.Use (a + b)(a − b) = a² − b² to find 27 × 13.
- 5.If a − b = 9 and ab = 36, what is a² + b²?
- 6.Use (a + b)² = a² + 2ab + b² to find 106².
- 7.Use (a − b)² = a² − 2ab + b² to find 55².
- 8.Use (a + b)(a − b) = a² − b² to find 106 × 94.
- 9.Use (a + b)² = a² + 2ab + b² to find 52².
- 10.Find the value of x² + 2xy + y² when x = 9 and y = 8.
- 11.Use a² − b² = (a + b)(a − b) to find 81² − 57².
- 12.Use (a − b)² = a² − 2ab + b² to find 87².
- 13.Use a² − b² = (a + b)(a − b) to find 24² − 22².
- 14.Find the value of x² + 2xy + y² when x = 5 and y = 1.
- 15.Use (a + b)(a − b) = a² − b² to find 33 × 27.
- 16.Use (a + b)(a − b) = a² − b² to find 66 × 54.
- 17.Use (a + b)² = a² + 2ab + b² to find 101².
- 18.Use (a − b)² = a² − 2ab + b² to find 53².
- 19.Use (a + b)(a − b) = a² − b² to find 24 × 16.
- 20.If a − b = 2 and ab = 3, what is a² + b²?
- 21.Use (a + b)(a − b) = a² − b² to find 46 × 34.
- 22.Use (a + b)² = a² + 2ab + b² to find 74².
- 23.Use (a − b)² = a² − 2ab + b² to find 67².
- 24.Use (a + b)² = a² + 2ab + b² to find 19².
- 25.Use (a − b)² = a² − 2ab + b² to find 94².
- 26.If a − b = 8 and ab = 9, what is a² + b²?
- 27.Use (a + b)(a − b) = a² − b² to find 69 × 51.
- 28.Find the value of x² − y² when x = 7 and y = 1.
- 29.Use (a − b)² = a² − 2ab + b² to find 37².
- 30.Use (a + b)² = a² + 2ab + b² to find 18².
- 31.Use (a + b)² = a² + 2ab + b² to find 83².
- 32.Use a² − b² = (a + b)(a − b) to find 82² − 71².
- 33.If a − b = 8 and ab = 33, what is a² + b²?
- 34.Use (a + b)² = a² + 2ab + b² to find 61².
- 35.Use a² − b² = (a + b)(a − b) to find 27² − 8².
- 36.Find the value of x² − y² when x = 4 and y = 3.
- 37.Find the value of x² + 2xy + y² when x = 5 and y = 3.
- 38.Use (a − b)² = a² − 2ab + b² to find 82².
- 39.Use (a + b)² = a² + 2ab + b² to find 79².
- 40.Find the value of x² − 2xy + y² when x = 14 and y = 13.
Answer key
- 193
- 25
- 287
- 351
- 153
- 11236
- 3025
- 9964
- 2704
- 289
- 3312
- 7569
- 92
- 36
- 891
- 3564
- 10201
- 2809
- 384
- 10
- 1564
- 5476
- 4489
- 361
- 8836
- 82
- 3519
- 48
- 1369
- 324
- 6889
- 1683
- 130
- 3721
- 665
- 7
- 64
- 6724
- 6241
- 1
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