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 53² − 39².
- 2.Find the value of x² + 2xy + y² when x = 7 and y = 3.
- 3.Use (a − b)² = a² − 2ab + b² to find 34².
- 4.Use (a − b)² = a² − 2ab + b² to find 54².
- 5.Find the value of x² + 2xy + y² when x = 6 and y = 4.
- 6.Find the value of x² − y² when x = 3 and y = 2.
- 7.Use (a + b)(a − b) = a² − b² to find 31 × 29.
- 8.Use a² − b² = (a + b)(a − b) to find 69² − 51².
- 9.Use (a + b)(a − b) = a² − b² to find 43 × 37.
- 10.Use (a + b)² = a² + 2ab + b² to find 99².
- 11.Use (a + b)(a − b) = a² − b² to find 82 × 78.
- 12.Use (a + b)(a − b) = a² − b² to find 52 × 48.
- 13.Use (a + b)² = a² + 2ab + b² to find 36².
- 14.If a + b = 5 and ab = 6, what is a² + b²?
- 15.Use (a − b)² = a² − 2ab + b² to find 64².
- 16.Find the value of x² − 2xy + y² when x = 10 and y = 3.
- 17.Use (a − b)² = a² − 2ab + b² to find 31².
- 18.Use (a + b)² = a² + 2ab + b² to find 96².
- 19.Use (a + b)² = a² + 2ab + b² to find 25².
- 20.Use a² − b² = (a + b)(a − b) to find 59² − 47².
- 21.Use (a − b)² = a² − 2ab + b² to find 52².
- 22.Find the value of x² + 2xy + y² when x = 4 and y = 1.
- 23.Find the value of x² + 2xy + y² when x = 9 and y = 5.
- 24.Use (a − b)² = a² − 2ab + b² to find 97².
- 25.If a − b = 5 and ab = 24, what is a² + b²?
- 26.Use (a − b)² = a² − 2ab + b² to find 73².
- 27.If a + b = 4 and ab = 3, what is a² + b²?
- 28.Use a² − b² = (a + b)(a − b) to find 44² − 1².
- 29.Use (a + b)² = a² + 2ab + b² to find 75².
- 30.Use (a + b)(a − b) = a² − b² to find 103 × 97.
- 31.Find the value of x² − 2xy + y² when x = 13 and y = 4.
- 32.Use (a + b)² = a² + 2ab + b² to find 22².
- 33.Use (a + b)(a − b) = a² − b² to find 86 × 74.
- 34.Find the value of x² + 2xy + y² when x = 14 and y = 5.
- 35.Use (a − b)² = a² − 2ab + b² to find 28².
- 36.Find the value of x² − y² when x = 10 and y = 2.
- 37.Use a² − b² = (a + b)(a − b) to find 82² − 79².
- 38.Use (a + b)(a − b) = a² − b² to find 39 × 21.
- 39.Use (a − b)² = a² − 2ab + b² to find 55².
- 40.Use (a − b)² = a² − 2ab + b² to find 35².
Answer key
- 1288
- 100
- 1156
- 2916
- 100
- 5
- 899
- 2160
- 1591
- 9801
- 6396
- 2496
- 1296
- 13
- 4096
- 49
- 961
- 9216
- 625
- 1272
- 2704
- 25
- 196
- 9409
- 73
- 5329
- 10
- 1935
- 5625
- 9991
- 81
- 484
- 6364
- 361
- 784
- 96
- 483
- 819
- 3025
- 1225
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