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 101².
- 2.Use a² − b² = (a + b)(a − b) to find 52² − 31².
- 3.Use a² − b² = (a + b)(a − b) to find 23² − 18².
- 4.If a − b = 2 and ab = 63, what is a² + b²?
- 5.Use (a + b)² = a² + 2ab + b² to find 66².
- 6.Use (a + b)(a − b) = a² − b² to find 57 × 43.
- 7.Use (a − b)² = a² − 2ab + b² to find 93².
- 8.If a − b = 1 and ab = 6, what is a² + b²?
- 9.Use (a + b)(a − b) = a² − b² to find 45 × 35.
- 10.Use (a − b)² = a² − 2ab + b² to find 71².
- 11.Use (a + b)² = a² + 2ab + b² to find 24².
- 12.Find the value of x² − 2xy + y² when x = 9 and y = 8.
- 13.If a + b = 3 and ab = 2, what is a² + b²?
- 14.Use (a − b)² = a² − 2ab + b² to find 52².
- 15.Use (a + b)² = a² + 2ab + b² to find 63².
- 16.If a + b = 4 and ab = 3, what is a² + b²?
- 17.Find the value of x² + 2xy + y² when x = 9 and y = 6.
- 18.Use a² − b² = (a + b)(a − b) to find 26² − 19².
- 19.Use (a + b)² = a² + 2ab + b² to find 36².
- 20.Use (a − b)² = a² − 2ab + b² to find 57².
- 21.Use (a + b)(a − b) = a² − b² to find 72 × 68.
- 22.Use (a + b)(a − b) = a² − b² to find 82 × 78.
- 23.Find the value of x² + 2xy + y² when x = 10 and y = 9.
- 24.If a + b = 5 and ab = 4, what is a² + b²?
- 25.If a − b = 4 and ab = 5, what is a² + b²?
- 26.Find the value of x² − y² when x = 10 and y = 7.
- 27.Find the value of x² − y² when x = 8 and y = 5.
- 28.Use (a − b)² = a² − 2ab + b² to find 65².
- 29.Use (a − b)² = a² − 2ab + b² to find 34².
- 30.Use (a + b)² = a² + 2ab + b² to find 43².
- 31.Use (a + b)(a − b) = a² − b² to find 92 × 88.
- 32.Use (a + b)² = a² + 2ab + b² to find 102².
- 33.Use (a − b)² = a² − 2ab + b² to find 75².
- 34.Use (a + b)² = a² + 2ab + b² to find 88².
- 35.Find the value of x² − y² when x = 4 and y = 3.
- 36.If a − b = 1 and ab = 2, what is a² + b²?
- 37.Use (a + b)(a − b) = a² − b² to find 32 × 28.
- 38.If a + b = 12 and ab = 32, what is a² + b²?
- 39.Use (a + b)² = a² + 2ab + b² to find 51².
- 40.Use a² − b² = (a + b)(a − b) to find 52² − 2².
Answer key
- 10201
- 1743
- 205
- 130
- 4356
- 2451
- 8649
- 13
- 1575
- 5041
- 576
- 1
- 5
- 2704
- 3969
- 10
- 225
- 315
- 1296
- 3249
- 4896
- 6396
- 361
- 17
- 26
- 51
- 39
- 4225
- 1156
- 1849
- 8096
- 10404
- 5625
- 7744
- 7
- 5
- 896
- 80
- 2601
- 2700
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