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 a² − b² = (a + b)(a − b) to find 55² − 3².
- 2.Find the value of x² − y² when x = 10 and y = 5.
- 3.Use (a + b)² = a² + 2ab + b² to find 46².
- 4.Use (a + b)(a − b) = a² − b² to find 41 × 39.
- 5.Use (a + b)² = a² + 2ab + b² to find 81².
- 6.Use (a + b)(a − b) = a² − b² to find 64 × 56.
- 7.Find the value of x² − 2xy + y² when x = 13 and y = 10.
- 8.Use a² − b² = (a + b)(a − b) to find 40² − 25².
- 9.Use (a + b)(a − b) = a² − b² to find 107 × 93.
- 10.Use (a + b)(a − b) = a² − b² to find 102 × 98.
- 11.Use (a + b)² = a² + 2ab + b² to find 56².
- 12.Use a² − b² = (a + b)(a − b) to find 98² − 94².
- 13.Find the value of x² − 2xy + y² when x = 4 and y = 2.
- 14.Find the value of x² + 2xy + y² when x = 8 and y = 7.
- 15.Use (a + b)(a − b) = a² − b² to find 76 × 64.
- 16.Use a² − b² = (a + b)(a − b) to find 59² − 31².
- 17.If a + b = 18 and ab = 80, what is a² + b²?
- 18.Use (a + b)(a − b) = a² − b² to find 93 × 87.
- 19.Use (a + b)² = a² + 2ab + b² to find 22².
- 20.Find the value of x² − 2xy + y² when x = 15 and y = 5.
- 21.Use (a + b)² = a² + 2ab + b² to find 91².
- 22.Find the value of x² − 2xy + y² when x = 8 and y = 5.
- 23.Use (a − b)² = a² − 2ab + b² to find 13².
- 24.Use a² − b² = (a + b)(a − b) to find 42² − 10².
- 25.If a + b = 4 and ab = 3, what is a² + b²?
- 26.Use (a + b)(a − b) = a² − b² to find 66 × 54.
- 27.Use (a + b)(a − b) = a² − b² to find 81 × 79.
- 28.Use (a − b)² = a² − 2ab + b² to find 56².
- 29.Use (a − b)² = a² − 2ab + b² to find 31².
- 30.Find the value of x² − y² when x = 7 and y = 3.
- 31.If a + b = 10 and ab = 24, what is a² + b²?
- 32.Use (a − b)² = a² − 2ab + b² to find 97².
- 33.If a − b = 2 and ab = 8, what is a² + b²?
- 34.Use a² − b² = (a + b)(a − b) to find 60² − 5².
- 35.Use (a − b)² = a² − 2ab + b² to find 99².
- 36.Use (a + b)(a − b) = a² − b² to find 68 × 52.
- 37.Find the value of x² − y² when x = 9 and y = 3.
- 38.Use a² − b² = (a + b)(a − b) to find 67² − 23².
- 39.Use a² − b² = (a + b)(a − b) to find 89² − 29².
- 40.Use (a − b)² = a² − 2ab + b² to find 71².
Answer key
- 3016
- 75
- 2116
- 1599
- 6561
- 3584
- 9
- 975
- 9951
- 9996
- 3136
- 768
- 4
- 225
- 4864
- 2520
- 164
- 8091
- 484
- 100
- 8281
- 9
- 169
- 1664
- 10
- 3564
- 6399
- 3136
- 961
- 40
- 52
- 9409
- 20
- 3575
- 9801
- 3536
- 72
- 3960
- 7080
- 5041
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