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 − 2xy + y² when x = 7 and y = 5.
- 2.Use (a + b)(a − b) = a² − b² to find 73 × 67.
- 3.Use a² − b² = (a + b)(a − b) to find 64² − 23².
- 4.Find the value of x² + 2xy + y² when x = 13 and y = 4.
- 5.If a − b = 7 and ab = 8, what is a² + b²?
- 6.Use a² − b² = (a + b)(a − b) to find 52² − 27².
- 7.Use (a − b)² = a² − 2ab + b² to find 73².
- 8.Use (a + b)(a − b) = a² − b² to find 43 × 37.
- 9.Use (a + b)(a − b) = a² − b² to find 35 × 25.
- 10.Find the value of x² − 2xy + y² when x = 3 and y = 2.
- 11.If a + b = 5 and ab = 6, what is a² + b²?
- 12.Use (a + b)(a − b) = a² − b² to find 24 × 16.
- 13.If a − b = 9 and ab = 36, what is a² + b²?
- 14.Use (a − b)² = a² − 2ab + b² to find 61².
- 15.Use a² − b² = (a + b)(a − b) to find 82² − 80².
- 16.Use (a + b)² = a² + 2ab + b² to find 94².
- 17.Use (a + b)(a − b) = a² − b² to find 88 × 72.
- 18.Use (a + b)² = a² + 2ab + b² to find 89².
- 19.Find the value of x² − y² when x = 7 and y = 2.
- 20.Find the value of x² − 2xy + y² when x = 7 and y = 2.
- 21.Use (a + b)² = a² + 2ab + b² to find 66².
- 22.Use (a − b)² = a² − 2ab + b² to find 62².
- 23.Use (a − b)² = a² − 2ab + b² to find 71².
- 24.Use (a + b)² = a² + 2ab + b² to find 15².
- 25.Use (a − b)² = a² − 2ab + b² to find 59².
- 26.If a − b = 6 and ab = 40, what is a² + b²?
- 27.Use (a + b)(a − b) = a² − b² to find 36 × 24.
- 28.If a + b = 4 and ab = 3, what is a² + b²?
- 29.Use (a + b)² = a² + 2ab + b² to find 104².
- 30.Use (a − b)² = a² − 2ab + b² to find 72².
- 31.Use (a + b)² = a² + 2ab + b² to find 58².
- 32.Use (a + b)² = a² + 2ab + b² to find 36².
- 33.Use a² − b² = (a + b)(a − b) to find 63² − 13².
- 34.Find the value of x² + 2xy + y² when x = 4 and y = 1.
- 35.Use (a − b)² = a² − 2ab + b² to find 28².
- 36.Use a² − b² = (a + b)(a − b) to find 55² − 34².
- 37.Use (a + b)² = a² + 2ab + b² to find 12².
- 38.Find the value of x² − y² when x = 6 and y = 4.
- 39.If a − b = 4 and ab = 21, what is a² + b²?
- 40.Use a² − b² = (a + b)(a − b) to find 56² − 50².
Answer key
- 4
- 4891
- 3567
- 289
- 65
- 1975
- 5329
- 1591
- 875
- 1
- 13
- 384
- 153
- 3721
- 324
- 8836
- 6336
- 7921
- 45
- 25
- 4356
- 3844
- 5041
- 225
- 3481
- 116
- 864
- 10
- 10816
- 5184
- 3364
- 1296
- 3800
- 25
- 784
- 1869
- 144
- 20
- 58
- 636
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