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 43².
- 2.Use (a + b)² = a² + 2ab + b² to find 49².
- 3.Use (a − b)² = a² − 2ab + b² to find 26².
- 4.If a − b = 1 and ab = 2, what is a² + b²?
- 5.Use a² − b² = (a + b)(a − b) to find 72² − 33².
- 6.Find the value of x² − y² when x = 12 and y = 2.
- 7.Find the value of x² − 2xy + y² when x = 14 and y = 11.
- 8.Use a² − b² = (a + b)(a − b) to find 25² − 2².
- 9.Use a² − b² = (a + b)(a − b) to find 24² − 16².
- 10.Use (a + b)(a − b) = a² − b² to find 73 × 67.
- 11.Use (a + b)(a − b) = a² − b² to find 56 × 44.
- 12.Use a² − b² = (a + b)(a − b) to find 27² − 13².
- 13.Use (a + b)(a − b) = a² − b² to find 98 × 82.
- 14.Use (a + b)(a − b) = a² − b² to find 25 × 15.
- 15.If a + b = 5 and ab = 6, what is a² + b²?
- 16.Use (a − b)² = a² − 2ab + b² to find 75².
- 17.If a − b = 6 and ab = 40, what is a² + b²?
- 18.Use a² − b² = (a + b)(a − b) to find 55² − 35².
- 19.Find the value of x² − y² when x = 9 and y = 1.
- 20.Use a² − b² = (a + b)(a − b) to find 25² − 10².
- 21.Find the value of x² + 2xy + y² when x = 6 and y = 5.
- 22.Use (a + b)(a − b) = a² − b² to find 103 × 97.
- 23.Use (a + b)² = a² + 2ab + b² to find 41².
- 24.Find the value of x² + 2xy + y² when x = 4 and y = 2.
- 25.If a + b = 5 and ab = 4, what is a² + b²?
- 26.Use (a + b)² = a² + 2ab + b² to find 14².
- 27.Use a² − b² = (a + b)(a − b) to find 21² − 6².
- 28.Use (a − b)² = a² − 2ab + b² to find 25².
- 29.Use (a − b)² = a² − 2ab + b² to find 39².
- 30.Use (a − b)² = a² − 2ab + b² to find 44².
- 31.Use a² − b² = (a + b)(a − b) to find 81² − 21².
- 32.Use (a + b)² = a² + 2ab + b² to find 97².
- 33.Use (a + b)² = a² + 2ab + b² to find 56².
- 34.Find the value of x² − y² when x = 3 and y = 1.
- 35.Use a² − b² = (a + b)(a − b) to find 60² − 58².
- 36.Use (a + b)(a − b) = a² − b² to find 22 × 18.
- 37.Use (a + b)² = a² + 2ab + b² to find 42².
- 38.Use a² − b² = (a + b)(a − b) to find 52² − 5².
- 39.Find the value of x² − 2xy + y² when x = 5 and y = 4.
- 40.If a − b = 4 and ab = 12, what is a² + b²?
Answer key
- 1849
- 2401
- 676
- 5
- 4095
- 140
- 9
- 621
- 320
- 4891
- 2464
- 560
- 8036
- 375
- 13
- 5625
- 116
- 1800
- 80
- 525
- 121
- 9991
- 1681
- 36
- 17
- 196
- 405
- 625
- 1521
- 1936
- 6120
- 9409
- 3136
- 8
- 236
- 396
- 1764
- 2679
- 1
- 40
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