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 70² − 67².
- 2.Use (a + b)(a − b) = a² − b² to find 34 × 26.
- 3.Use a² − b² = (a + b)(a − b) to find 98² − 14².
- 4.Find the value of x² + 2xy + y² when x = 10 and y = 5.
- 5.Use (a + b)² = a² + 2ab + b² to find 12².
- 6.If a − b = 2 and ab = 3, what is a² + b²?
- 7.Use a² − b² = (a + b)(a − b) to find 37² − 6².
- 8.If a − b = 1 and ab = 132, what is a² + b²?
- 9.If a − b = 7 and ab = 44, what is a² + b²?
- 10.If a + b = 13 and ab = 30, what is a² + b²?
- 11.If a + b = 10 and ab = 9, what is a² + b²?
- 12.Use (a + b)² = a² + 2ab + b² to find 63².
- 13.Use (a + b)(a − b) = a² − b² to find 25 × 15.
- 14.Find the value of x² − y² when x = 5 and y = 3.
- 15.Use (a − b)² = a² − 2ab + b² to find 76².
- 16.If a + b = 5 and ab = 6, what is a² + b²?
- 17.Use (a − b)² = a² − 2ab + b² to find 25².
- 18.Use (a − b)² = a² − 2ab + b² to find 22².
- 19.If a + b = 8 and ab = 7, what is a² + b²?
- 20.Use (a + b)² = a² + 2ab + b² to find 76².
- 21.Use (a − b)² = a² − 2ab + b² to find 78².
- 22.Use (a − b)² = a² − 2ab + b² to find 51².
- 23.If a + b = 5 and ab = 4, what is a² + b²?
- 24.Use (a + b)(a − b) = a² − b² to find 49 × 31.
- 25.If a − b = 1 and ab = 2, what is a² + b²?
- 26.Find the value of x² + 2xy + y² when x = 14 and y = 5.
- 27.Use (a − b)² = a² − 2ab + b² to find 21².
- 28.Use (a + b)² = a² + 2ab + b² to find 99².
- 29.Use (a + b)² = a² + 2ab + b² to find 28².
- 30.Use a² − b² = (a + b)(a − b) to find 32² − 27².
- 31.Find the value of x² − y² when x = 14 and y = 13.
- 32.If a − b = 4 and ab = 60, what is a² + b²?
- 33.Use (a − b)² = a² − 2ab + b² to find 61².
- 34.Use (a + b)² = a² + 2ab + b² to find 62².
- 35.Use (a − b)² = a² − 2ab + b² to find 19².
- 36.Use a² − b² = (a + b)(a − b) to find 58² − 16².
- 37.Use (a + b)² = a² + 2ab + b² to find 45².
- 38.Use (a + b)² = a² + 2ab + b² to find 65².
- 39.Find the value of x² + 2xy + y² when x = 6 and y = 5.
- 40.Use (a − b)² = a² − 2ab + b² to find 46².
Answer key
- 411
- 884
- 9408
- 225
- 144
- 10
- 1333
- 265
- 137
- 109
- 82
- 3969
- 375
- 16
- 5776
- 13
- 625
- 484
- 50
- 5776
- 6084
- 2601
- 17
- 1519
- 5
- 361
- 441
- 9801
- 784
- 295
- 27
- 136
- 3721
- 3844
- 361
- 3108
- 2025
- 4225
- 121
- 2116
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