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)² = a² − 2ab + b² to find 85².
- 2.If a − b = 2 and ab = 3, what is a² + b²?
- 3.Use (a − b)² = a² − 2ab + b² to find 58².
- 4.Use a² − b² = (a + b)(a − b) to find 88² − 74².
- 5.Use (a − b)² = a² − 2ab + b² to find 16².
- 6.If a − b = 3 and ab = 108, what is a² + b²?
- 7.Find the value of x² + 2xy + y² when x = 9 and y = 2.
- 8.Find the value of x² + 2xy + y² when x = 5 and y = 1.
- 9.Use a² − b² = (a + b)(a − b) to find 89² − 16².
- 10.Find the value of x² − 2xy + y² when x = 14 and y = 6.
- 11.Use (a + b)² = a² + 2ab + b² to find 61².
- 12.Use a² − b² = (a + b)(a − b) to find 58² − 47².
- 13.If a + b = 20 and ab = 96, what is a² + b²?
- 14.Use (a + b)² = a² + 2ab + b² to find 71².
- 15.Use a² − b² = (a + b)(a − b) to find 72² − 6².
- 16.Use (a + b)² = a² + 2ab + b² to find 52².
- 17.Use (a − b)² = a² − 2ab + b² to find 37².
- 18.Use (a + b)² = a² + 2ab + b² to find 58².
- 19.Use (a + b)² = a² + 2ab + b² to find 73².
- 20.Use (a − b)² = a² − 2ab + b² to find 71².
- 21.Use (a − b)² = a² − 2ab + b² to find 88².
- 22.If a + b = 9 and ab = 18, what is a² + b²?
- 23.Use a² − b² = (a + b)(a − b) to find 63² − 49².
- 24.Find the value of x² − 2xy + y² when x = 6 and y = 2.
- 25.Use (a − b)² = a² − 2ab + b² to find 39².
- 26.Use a² − b² = (a + b)(a − b) to find 96² − 62².
- 27.Use a² − b² = (a + b)(a − b) to find 61² − 23².
- 28.Use (a + b)² = a² + 2ab + b² to find 14².
- 29.Use (a + b)² = a² + 2ab + b² to find 13².
- 30.Use (a + b)² = a² + 2ab + b² to find 94².
- 31.Use (a + b)² = a² + 2ab + b² to find 95².
- 32.Find the value of x² − 2xy + y² when x = 7 and y = 4.
- 33.If a + b = 21 and ab = 110, what is a² + b²?
- 34.Use (a + b)(a − b) = a² − b² to find 28 × 12.
- 35.Use (a − b)² = a² − 2ab + b² to find 65².
- 36.Use (a − b)² = a² − 2ab + b² to find 62².
- 37.Use (a − b)² = a² − 2ab + b² to find 19².
- 38.Use a² − b² = (a + b)(a − b) to find 29² − 4².
- 39.Use a² − b² = (a + b)(a − b) to find 29² − 5².
- 40.Use a² − b² = (a + b)(a − b) to find 68² − 49².
Answer key
- 7225
- 10
- 3364
- 2268
- 256
- 225
- 121
- 36
- 7665
- 64
- 3721
- 1155
- 208
- 5041
- 5148
- 2704
- 1369
- 3364
- 5329
- 5041
- 7744
- 45
- 1568
- 16
- 1521
- 5372
- 3192
- 196
- 169
- 8836
- 9025
- 9
- 221
- 336
- 4225
- 3844
- 361
- 825
- 816
- 2223
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