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 65².
- 2.Use (a + b)² = a² + 2ab + b² to find 33².
- 3.Use (a + b)² = a² + 2ab + b² to find 18².
- 4.Use a² − b² = (a + b)(a − b) to find 85² − 20².
- 5.Use (a + b)(a − b) = a² − b² to find 23 × 17.
- 6.If a − b = 3 and ab = 10, what is a² + b²?
- 7.Use a² − b² = (a + b)(a − b) to find 94² − 57².
- 8.If a + b = 11 and ab = 24, what is a² + b²?
- 9.Use (a + b)² = a² + 2ab + b² to find 44².
- 10.Use (a − b)² = a² − 2ab + b² to find 66².
- 11.Use (a − b)² = a² − 2ab + b² to find 97².
- 12.If a + b = 5 and ab = 6, what is a² + b²?
- 13.Use (a − b)² = a² − 2ab + b² to find 49².
- 14.If a + b = 6 and ab = 5, what is a² + b²?
- 15.If a − b = 1 and ab = 2, what is a² + b²?
- 16.Use a² − b² = (a + b)(a − b) to find 31² − 1².
- 17.Use (a − b)² = a² − 2ab + b² to find 47².
- 18.Use (a − b)² = a² − 2ab + b² to find 73².
- 19.Use (a + b)² = a² + 2ab + b² to find 76².
- 20.Find the value of x² + 2xy + y² when x = 11 and y = 2.
- 21.Find the value of x² − 2xy + y² when x = 8 and y = 3.
- 22.Use (a − b)² = a² − 2ab + b² to find 83².
- 23.Use a² − b² = (a + b)(a − b) to find 22² − 19².
- 24.Use (a + b)² = a² + 2ab + b² to find 25².
- 25.Use (a + b)(a − b) = a² − b² to find 97 × 83.
- 26.Use (a − b)² = a² − 2ab + b² to find 21².
- 27.If a + b = 4 and ab = 3, what is a² + b²?
- 28.If a − b = 2 and ab = 24, what is a² + b²?
- 29.Use (a − b)² = a² − 2ab + b² to find 59².
- 30.Use (a + b)² = a² + 2ab + b² to find 103².
- 31.Use (a + b)(a − b) = a² − b² to find 81 × 79.
- 32.Use (a − b)² = a² − 2ab + b² to find 68².
- 33.Find the value of x² − y² when x = 8 and y = 6.
- 34.Use (a − b)² = a² − 2ab + b² to find 31².
- 35.Use (a + b)(a − b) = a² − b² to find 46 × 34.
- 36.If a − b = 7 and ab = 44, what is a² + b²?
- 37.Find the value of x² + 2xy + y² when x = 13 and y = 2.
- 38.Find the value of x² − y² when x = 10 and y = 9.
- 39.If a + b = 7 and ab = 6, what is a² + b²?
- 40.Find the value of x² − 2xy + y² when x = 5 and y = 2.
Answer key
- 4225
- 1089
- 324
- 6825
- 391
- 29
- 5587
- 73
- 1936
- 4356
- 9409
- 13
- 2401
- 26
- 5
- 960
- 2209
- 5329
- 5776
- 169
- 25
- 6889
- 123
- 625
- 8051
- 441
- 10
- 52
- 3481
- 10609
- 6399
- 4624
- 28
- 961
- 1564
- 137
- 225
- 19
- 37
- 9
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