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 28².
- 2.Use a² − b² = (a + b)(a − b) to find 54² − 42².
- 3.Use (a − b)² = a² − 2ab + b² to find 59².
- 4.Use (a − b)² = a² − 2ab + b² to find 63².
- 5.If a − b = 2 and ab = 3, what is a² + b²?
- 6.Use (a + b)² = a² + 2ab + b² to find 82².
- 7.Find the value of x² − 2xy + y² when x = 7 and y = 3.
- 8.Use (a − b)² = a² − 2ab + b² to find 56².
- 9.Find the value of x² − y² when x = 9 and y = 3.
- 10.Use (a − b)² = a² − 2ab + b² to find 58².
- 11.Use (a + b)² = a² + 2ab + b² to find 14².
- 12.Find the value of x² − 2xy + y² when x = 4 and y = 1.
- 13.Use a² − b² = (a + b)(a − b) to find 41² − 33².
- 14.Use a² − b² = (a + b)(a − b) to find 37² − 12².
- 15.Use a² − b² = (a + b)(a − b) to find 31² − 25².
- 16.Find the value of x² − 2xy + y² when x = 11 and y = 6.
- 17.Use (a + b)(a − b) = a² − b² to find 103 × 97.
- 18.Use (a + b)(a − b) = a² − b² to find 95 × 85.
- 19.Use (a − b)² = a² − 2ab + b² to find 37².
- 20.Use (a + b)(a − b) = a² − b² to find 23 × 17.
- 21.If a − b = 5 and ab = 24, what is a² + b²?
- 22.Use (a + b)² = a² + 2ab + b² to find 69².
- 23.Use (a + b)(a − b) = a² − b² to find 31 × 29.
- 24.Use (a + b)² = a² + 2ab + b² to find 52².
- 25.Use (a + b)² = a² + 2ab + b² to find 58².
- 26.Use (a − b)² = a² − 2ab + b² to find 67².
- 27.Find the value of x² − 2xy + y² when x = 4 and y = 2.
- 28.If a + b = 5 and ab = 6, what is a² + b²?
- 29.If a + b = 14 and ab = 45, what is a² + b²?
- 30.Use (a − b)² = a² − 2ab + b² to find 98².
- 31.Use (a + b)(a − b) = a² − b² to find 36 × 24.
- 32.Use (a − b)² = a² − 2ab + b² to find 43².
- 33.If a + b = 3 and ab = 2, what is a² + b²?
- 34.Use (a + b)(a − b) = a² − b² to find 107 × 93.
- 35.Use (a + b)(a − b) = a² − b² to find 52 × 48.
- 36.Use (a − b)² = a² − 2ab + b² to find 93².
- 37.Find the value of x² + 2xy + y² when x = 9 and y = 6.
- 38.Find the value of x² − 2xy + y² when x = 14 and y = 13.
- 39.Use (a − b)² = a² − 2ab + b² to find 94².
- 40.If a − b = 3 and ab = 4, what is a² + b²?
Answer key
- 784
- 1152
- 3481
- 3969
- 10
- 6724
- 16
- 3136
- 72
- 3364
- 196
- 9
- 592
- 1225
- 336
- 25
- 9991
- 8075
- 1369
- 391
- 73
- 4761
- 899
- 2704
- 3364
- 4489
- 4
- 13
- 106
- 9604
- 864
- 1849
- 5
- 9951
- 2496
- 8649
- 225
- 1
- 8836
- 17
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