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.Find the value of x² − y² when x = 15 and y = 13.
- 2.Use a² − b² = (a + b)(a − b) to find 88² − 15².
- 3.Use (a + b)² = a² + 2ab + b² to find 22².
- 4.Find the value of x² + 2xy + y² when x = 5 and y = 1.
- 5.Use (a + b)² = a² + 2ab + b² to find 44².
- 6.If a − b = 3 and ab = 54, what is a² + b²?
- 7.Use a² − b² = (a + b)(a − b) to find 43² − 31².
- 8.Find the value of x² + 2xy + y² when x = 7 and y = 5.
- 9.Use (a − b)² = a² − 2ab + b² to find 15².
- 10.Use (a + b)(a − b) = a² − b² to find 27 × 13.
- 11.Use (a + b)² = a² + 2ab + b² to find 75².
- 12.Use (a − b)² = a² − 2ab + b² to find 37².
- 13.Use (a − b)² = a² − 2ab + b² to find 12².
- 14.If a + b = 16 and ab = 60, what is a² + b²?
- 15.Use (a − b)² = a² − 2ab + b² to find 69².
- 16.Use (a + b)² = a² + 2ab + b² to find 107².
- 17.Use (a + b)(a − b) = a² − b² to find 77 × 63.
- 18.Use (a − b)² = a² − 2ab + b² to find 62².
- 19.Find the value of x² + 2xy + y² when x = 3 and y = 2.
- 20.Use (a + b)² = a² + 2ab + b² to find 12².
- 21.Use (a + b)(a − b) = a² − b² to find 37 × 23.
- 22.If a + b = 4 and ab = 3, what is a² + b²?
- 23.Find the value of x² − y² when x = 10 and y = 3.
- 24.If a + b = 10 and ab = 16, what is a² + b²?
- 25.Use a² − b² = (a + b)(a − b) to find 69² − 44².
- 26.Use (a − b)² = a² − 2ab + b² to find 82².
- 27.Find the value of x² − y² when x = 13 and y = 8.
- 28.Use (a − b)² = a² − 2ab + b² to find 94².
- 29.Use (a − b)² = a² − 2ab + b² to find 19².
- 30.Use (a + b)² = a² + 2ab + b² to find 29².
- 31.Use (a − b)² = a² − 2ab + b² to find 88².
- 32.If a + b = 10 and ab = 21, what is a² + b²?
- 33.Use (a + b)(a − b) = a² − b² to find 22 × 18.
- 34.Use (a + b)² = a² + 2ab + b² to find 21².
- 35.Use (a + b)² = a² + 2ab + b² to find 53².
- 36.Use (a − b)² = a² − 2ab + b² to find 63².
- 37.Use (a + b)(a − b) = a² − b² to find 21 × 19.
- 38.Use a² − b² = (a + b)(a − b) to find 50² − 39².
- 39.Use (a + b)² = a² + 2ab + b² to find 34².
- 40.If a − b = 2 and ab = 3, what is a² + b²?
Answer key
- 56
- 7519
- 484
- 36
- 1936
- 117
- 888
- 144
- 225
- 351
- 5625
- 1369
- 144
- 136
- 4761
- 11449
- 4851
- 3844
- 25
- 144
- 851
- 10
- 91
- 68
- 2825
- 6724
- 105
- 8836
- 361
- 841
- 7744
- 58
- 396
- 441
- 2809
- 3969
- 399
- 979
- 1156
- 10
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