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 45² − 26².
- 2.Use (a + b)² = a² + 2ab + b² to find 64².
- 3.If a − b = 8 and ab = 48, what is a² + b²?
- 4.Use a² − b² = (a + b)(a − b) to find 92² − 22².
- 5.Use (a − b)² = a² − 2ab + b² to find 62².
- 6.Use (a + b)² = a² + 2ab + b² to find 104².
- 7.Use (a + b)(a − b) = a² − b² to find 75 × 65.
- 8.Find the value of x² − 2xy + y² when x = 11 and y = 10.
- 9.Use (a + b)² = a² + 2ab + b² to find 31².
- 10.If a − b = 1 and ab = 72, what is a² + b²?
- 11.Use (a − b)² = a² − 2ab + b² to find 19².
- 12.Use (a + b)(a − b) = a² − b² to find 63 × 57.
- 13.Use (a + b)² = a² + 2ab + b² to find 106².
- 14.Find the value of x² + 2xy + y² when x = 3 and y = 1.
- 15.Use (a − b)² = a² − 2ab + b² to find 31².
- 16.Use (a − b)² = a² − 2ab + b² to find 66².
- 17.Use (a + b)(a − b) = a² − b² to find 22 × 18.
- 18.Use (a + b)(a − b) = a² − b² to find 27 × 13.
- 19.Use (a + b)² = a² + 2ab + b² to find 18².
- 20.Use (a + b)(a − b) = a² − b² to find 31 × 29.
- 21.Use (a + b)(a − b) = a² − b² to find 61 × 59.
- 22.Find the value of x² + 2xy + y² when x = 11 and y = 8.
- 23.Use a² − b² = (a + b)(a − b) to find 93² − 8².
- 24.Use (a − b)² = a² − 2ab + b² to find 42².
- 25.Use a² − b² = (a + b)(a − b) to find 55² − 49².
- 26.Find the value of x² + 2xy + y² when x = 13 and y = 10.
- 27.Use (a − b)² = a² − 2ab + b² to find 32².
- 28.Use (a + b)² = a² + 2ab + b² to find 58².
- 29.Use a² − b² = (a + b)(a − b) to find 26² − 22².
- 30.If a − b = 3 and ab = 108, what is a² + b²?
- 31.Use (a + b)(a − b) = a² − b² to find 98 × 82.
- 32.Use (a − b)² = a² − 2ab + b² to find 25².
- 33.If a + b = 7 and ab = 12, what is a² + b²?
- 34.If a + b = 5 and ab = 6, what is a² + b²?
- 35.Use (a + b)² = a² + 2ab + b² to find 102².
- 36.Use (a − b)² = a² − 2ab + b² to find 91².
- 37.Use (a + b)² = a² + 2ab + b² to find 24².
- 38.Use (a + b)(a − b) = a² − b² to find 43 × 37.
- 39.Use a² − b² = (a + b)(a − b) to find 26² − 3².
- 40.Use a² − b² = (a + b)(a − b) to find 84² − 21².
Answer key
- 1349
- 4096
- 160
- 7980
- 3844
- 10816
- 4875
- 1
- 961
- 145
- 361
- 3591
- 11236
- 16
- 961
- 4356
- 396
- 351
- 324
- 899
- 3599
- 361
- 8585
- 1764
- 624
- 529
- 1024
- 3364
- 192
- 225
- 8036
- 625
- 25
- 13
- 10404
- 8281
- 576
- 1591
- 667
- 6615
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