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 = 3 and y = 1.
- 2.Find the value of x² + 2xy + y² when x = 10 and y = 7.
- 3.If a − b = 1 and ab = 30, what is a² + b²?
- 4.If a − b = 1 and ab = 42, what is a² + b²?
- 5.If a + b = 3 and ab = 2, what is a² + b²?
- 6.If a + b = 5 and ab = 4, what is a² + b²?
- 7.If a + b = 9 and ab = 20, what is a² + b²?
- 8.Find the value of x² − y² when x = 8 and y = 7.
- 9.Use (a − b)² = a² − 2ab + b² to find 27².
- 10.Use a² − b² = (a + b)(a − b) to find 58² − 14².
- 11.Use (a + b)² = a² + 2ab + b² to find 53².
- 12.Use (a + b)² = a² + 2ab + b² to find 47².
- 13.Find the value of x² − y² when x = 10 and y = 3.
- 14.Use a² − b² = (a + b)(a − b) to find 25² − 2².
- 15.Use (a + b)² = a² + 2ab + b² to find 38².
- 16.Find the value of x² − 2xy + y² when x = 9 and y = 2.
- 17.Use (a + b)² = a² + 2ab + b² to find 98².
- 18.If a + b = 14 and ab = 33, what is a² + b²?
- 19.Use (a − b)² = a² − 2ab + b² to find 55².
- 20.Use (a + b)² = a² + 2ab + b² to find 14².
- 21.Use a² − b² = (a + b)(a − b) to find 53² − 52².
- 22.Use (a + b)² = a² + 2ab + b² to find 54².
- 23.Use a² − b² = (a + b)(a − b) to find 65² − 14².
- 24.If a + b = 7 and ab = 12, what is a² + b²?
- 25.Use (a − b)² = a² − 2ab + b² to find 47².
- 26.Use (a + b)² = a² + 2ab + b² to find 25².
- 27.Use (a + b)(a − b) = a² − b² to find 97 × 83.
- 28.Use (a + b)(a − b) = a² − b² to find 102 × 98.
- 29.Find the value of x² − y² when x = 7 and y = 6.
- 30.Use (a + b)(a − b) = a² − b² to find 36 × 24.
- 31.Use (a + b)(a − b) = a² − b² to find 104 × 96.
- 32.Find the value of x² + 2xy + y² when x = 5 and y = 3.
- 33.Find the value of x² − y² when x = 12 and y = 8.
- 34.If a − b = 3 and ab = 10, what is a² + b²?
- 35.Use (a − b)² = a² − 2ab + b² to find 69².
- 36.Use (a + b)² = a² + 2ab + b² to find 105².
- 37.Use (a − b)² = a² − 2ab + b² to find 74².
- 38.Use (a − b)² = a² − 2ab + b² to find 19².
- 39.Use (a + b)² = a² + 2ab + b² to find 108².
- 40.Find the value of x² + 2xy + y² when x = 13 and y = 10.
Answer key
- 16
- 289
- 61
- 85
- 5
- 17
- 41
- 15
- 729
- 3168
- 2809
- 2209
- 91
- 621
- 1444
- 49
- 9604
- 130
- 3025
- 196
- 105
- 2916
- 4029
- 25
- 2209
- 625
- 8051
- 9996
- 13
- 864
- 9984
- 64
- 80
- 29
- 4761
- 11025
- 5476
- 361
- 11664
- 529
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