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 75².
- 2.Find the value of x² − y² when x = 12 and y = 6.
- 3.Find the value of x² − 2xy + y² when x = 8 and y = 7.
- 4.Use a² − b² = (a + b)(a − b) to find 25² − 24².
- 5.If a + b = 7 and ab = 12, what is a² + b²?
- 6.Use (a − b)² = a² − 2ab + b² to find 87².
- 7.Use (a + b)(a − b) = a² − b² to find 101 × 99.
- 8.Use (a + b)² = a² + 2ab + b² to find 22².
- 9.Use (a + b)² = a² + 2ab + b² to find 32².
- 10.Use (a − b)² = a² − 2ab + b² to find 44².
- 11.Use (a + b)(a − b) = a² − b² to find 45 × 35.
- 12.Use (a − b)² = a² − 2ab + b² to find 56².
- 13.Use (a − b)² = a² − 2ab + b² to find 48².
- 14.Find the value of x² − y² when x = 6 and y = 1.
- 15.Use (a + b)² = a² + 2ab + b² to find 31².
- 16.Use (a + b)(a − b) = a² − b² to find 92 × 88.
- 17.Use a² − b² = (a + b)(a − b) to find 46² − 38².
- 18.Use (a − b)² = a² − 2ab + b² to find 84².
- 19.Use (a + b)² = a² + 2ab + b² to find 63².
- 20.Find the value of x² − 2xy + y² when x = 6 and y = 5.
- 21.Use a² − b² = (a + b)(a − b) to find 45² − 39².
- 22.Use a² − b² = (a + b)(a − b) to find 84² − 14².
- 23.Use (a + b)² = a² + 2ab + b² to find 83².
- 24.Use (a − b)² = a² − 2ab + b² to find 38².
- 25.If a + b = 3 and ab = 2, what is a² + b²?
- 26.Use (a − b)² = a² − 2ab + b² to find 65².
- 27.Use (a + b)² = a² + 2ab + b² to find 61².
- 28.Use (a + b)(a − b) = a² − b² to find 104 × 96.
- 29.Use a² − b² = (a + b)(a − b) to find 48² − 11².
- 30.Find the value of x² − y² when x = 6 and y = 3.
- 31.Use (a + b)(a − b) = a² − b² to find 93 × 87.
- 32.Use a² − b² = (a + b)(a − b) to find 42² − 7².
- 33.Find the value of x² + 2xy + y² when x = 11 and y = 4.
- 34.Find the value of x² − y² when x = 13 and y = 1.
- 35.Use (a + b)(a − b) = a² − b² to find 49 × 31.
- 36.Find the value of x² + 2xy + y² when x = 10 and y = 3.
- 37.Use (a − b)² = a² − 2ab + b² to find 91².
- 38.Use (a + b)(a − b) = a² − b² to find 63 × 57.
- 39.Use a² − b² = (a + b)(a − b) to find 32² − 2².
- 40.Use (a + b)² = a² + 2ab + b² to find 45².
Answer key
- 5625
- 108
- 1
- 49
- 25
- 7569
- 9999
- 484
- 1024
- 1936
- 1575
- 3136
- 2304
- 35
- 961
- 8096
- 672
- 7056
- 3969
- 1
- 504
- 6860
- 6889
- 1444
- 5
- 4225
- 3721
- 9984
- 2183
- 27
- 8091
- 1715
- 225
- 168
- 1519
- 169
- 8281
- 3591
- 1020
- 2025
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