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 34² − 1².
- 2.Use (a + b)(a − b) = a² − b² to find 46 × 34.
- 3.Use a² − b² = (a + b)(a − b) to find 32² − 1².
- 4.If a − b = 2 and ab = 3, what is a² + b²?
- 5.Use (a + b)² = a² + 2ab + b² to find 31².
- 6.Use (a + b)(a − b) = a² − b² to find 48 × 32.
- 7.Use (a + b)(a − b) = a² − b² to find 61 × 59.
- 8.Find the value of x² − 2xy + y² when x = 12 and y = 3.
- 9.Use (a + b)(a − b) = a² − b² to find 93 × 87.
- 10.Find the value of x² − y² when x = 7 and y = 6.
- 11.Use (a + b)(a − b) = a² − b² to find 23 × 17.
- 12.Find the value of x² − 2xy + y² when x = 7 and y = 5.
- 13.Use (a + b)² = a² + 2ab + b² to find 39².
- 14.Use (a + b)² = a² + 2ab + b² to find 54².
- 15.Use (a − b)² = a² − 2ab + b² to find 48².
- 16.If a + b = 17 and ab = 72, what is a² + b²?
- 17.Use (a − b)² = a² − 2ab + b² to find 18².
- 18.Use (a − b)² = a² − 2ab + b² to find 33².
- 19.Use a² − b² = (a + b)(a − b) to find 32² − 10².
- 20.Use (a + b)² = a² + 2ab + b² to find 77².
- 21.Use (a + b)² = a² + 2ab + b² to find 35².
- 22.Use (a + b)² = a² + 2ab + b² to find 18².
- 23.Find the value of x² + 2xy + y² when x = 15 and y = 14.
- 24.Use (a + b)² = a² + 2ab + b² to find 95².
- 25.Find the value of x² − 2xy + y² when x = 12 and y = 4.
- 26.Use (a + b)² = a² + 2ab + b² to find 107².
- 27.Use a² − b² = (a + b)(a − b) to find 90² − 42².
- 28.Find the value of x² + 2xy + y² when x = 13 and y = 10.
- 29.Use (a − b)² = a² − 2ab + b² to find 19².
- 30.Use (a − b)² = a² − 2ab + b² to find 86².
- 31.Use (a − b)² = a² − 2ab + b² to find 15².
- 32.Use (a − b)² = a² − 2ab + b² to find 41².
- 33.Find the value of x² − y² when x = 11 and y = 10.
- 34.Use a² − b² = (a + b)(a − b) to find 80² − 45².
- 35.Use a² − b² = (a + b)(a − b) to find 75² − 68².
- 36.Find the value of x² + 2xy + y² when x = 10 and y = 3.
- 37.Use (a + b)² = a² + 2ab + b² to find 37².
- 38.Use (a − b)² = a² − 2ab + b² to find 52².
- 39.Use (a + b)² = a² + 2ab + b² to find 24².
- 40.Use (a − b)² = a² − 2ab + b² to find 98².
Answer key
- 1155
- 1564
- 1023
- 10
- 961
- 1536
- 3599
- 81
- 8091
- 13
- 391
- 4
- 1521
- 2916
- 2304
- 145
- 324
- 1089
- 924
- 5929
- 1225
- 324
- 841
- 9025
- 64
- 11449
- 6336
- 529
- 361
- 7396
- 225
- 1681
- 21
- 4375
- 1001
- 169
- 1369
- 2704
- 576
- 9604
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