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 16².
- 2.Use (a + b)(a − b) = a² − b² to find 43 × 37.
- 3.Use (a + b)(a − b) = a² − b² to find 88 × 72.
- 4.Find the value of x² + 2xy + y² when x = 11 and y = 3.
- 5.Use (a − b)² = a² − 2ab + b² to find 79².
- 6.Use (a + b)² = a² + 2ab + b² to find 14².
- 7.Use (a + b)² = a² + 2ab + b² to find 104².
- 8.Find the value of x² − 2xy + y² when x = 7 and y = 5.
- 9.Use (a + b)² = a² + 2ab + b² to find 105².
- 10.If a + b = 9 and ab = 18, what is a² + b²?
- 11.Use (a + b)² = a² + 2ab + b² to find 73².
- 12.Use (a − b)² = a² − 2ab + b² to find 96².
- 13.If a − b = 5 and ab = 66, what is a² + b²?
- 14.Use (a − b)² = a² − 2ab + b² to find 61².
- 15.Use (a + b)(a − b) = a² − b² to find 66 × 54.
- 16.Use a² − b² = (a + b)(a − b) to find 91² − 56².
- 17.Use (a + b)(a − b) = a² − b² to find 35 × 25.
- 18.Find the value of x² − y² when x = 14 and y = 3.
- 19.Use (a + b)² = a² + 2ab + b² to find 75².
- 20.Use (a + b)² = a² + 2ab + b² to find 37².
- 21.Use (a + b)(a − b) = a² − b² to find 42 × 38.
- 22.Use (a + b)(a − b) = a² − b² to find 78 × 62.
- 23.Use (a + b)(a − b) = a² − b² to find 53 × 47.
- 24.Use a² − b² = (a + b)(a − b) to find 65² − 8².
- 25.Use (a + b)(a − b) = a² − b² to find 93 × 87.
- 26.Use (a + b)(a − b) = a² − b² to find 59 × 41.
- 27.Find the value of x² − y² when x = 5 and y = 4.
- 28.Use (a + b)(a − b) = a² − b² to find 58 × 42.
- 29.Use (a + b)² = a² + 2ab + b² to find 84².
- 30.Use (a − b)² = a² − 2ab + b² to find 63².
- 31.If a − b = 6 and ab = 27, what is a² + b²?
- 32.Use (a + b)(a − b) = a² − b² to find 86 × 74.
- 33.Use (a − b)² = a² − 2ab + b² to find 43².
- 34.Use (a + b)² = a² + 2ab + b² to find 63².
- 35.Use (a + b)(a − b) = a² − b² to find 82 × 78.
- 36.Use (a + b)(a − b) = a² − b² to find 55 × 45.
- 37.Find the value of x² − 2xy + y² when x = 3 and y = 1.
- 38.If a + b = 17 and ab = 70, what is a² + b²?
- 39.Use (a + b)(a − b) = a² − b² to find 54 × 46.
- 40.Use (a + b)² = a² + 2ab + b² to find 36².
Answer key
- 256
- 1591
- 6336
- 196
- 6241
- 196
- 10816
- 4
- 11025
- 45
- 5329
- 9216
- 157
- 3721
- 3564
- 5145
- 875
- 187
- 5625
- 1369
- 1596
- 4836
- 2491
- 4161
- 8091
- 2419
- 9
- 2436
- 7056
- 3969
- 90
- 6364
- 1849
- 3969
- 6396
- 2475
- 4
- 149
- 2484
- 1296
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