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.If a − b = 2 and ab = 8, what is a² + b²?
- 3.Find the value of x² − y² when x = 11 and y = 6.
- 4.Use (a + b)² = a² + 2ab + b² to find 43².
- 5.If a − b = 1 and ab = 72, what is a² + b²?
- 6.Use (a − b)² = a² − 2ab + b² to find 86².
- 7.Use a² − b² = (a + b)(a − b) to find 40² − 34².
- 8.Find the value of x² + 2xy + y² when x = 12 and y = 11.
- 9.Find the value of x² + 2xy + y² when x = 6 and y = 3.
- 10.Use (a + b)(a − b) = a² − b² to find 49 × 31.
- 11.Use (a − b)² = a² − 2ab + b² to find 87².
- 12.Use (a + b)² = a² + 2ab + b² to find 63².
- 13.Find the value of x² − y² when x = 4 and y = 1.
- 14.Use a² − b² = (a + b)(a − b) to find 57² − 52².
- 15.If a − b = 1 and ab = 6, what is a² + b²?
- 16.Use (a + b)² = a² + 2ab + b² to find 92².
- 17.Find the value of x² − y² when x = 10 and y = 1.
- 18.Use a² − b² = (a + b)(a − b) to find 40² − 39².
- 19.Use a² − b² = (a + b)(a − b) to find 87² − 36².
- 20.Use (a + b)² = a² + 2ab + b² to find 22².
- 21.Use (a − b)² = a² − 2ab + b² to find 75².
- 22.Use (a + b)(a − b) = a² − b² to find 95 × 85.
- 23.Use a² − b² = (a + b)(a − b) to find 39² − 6².
- 24.Use (a − b)² = a² − 2ab + b² to find 44².
- 25.Use (a + b)² = a² + 2ab + b² to find 53².
- 26.Use (a + b)² = a² + 2ab + b² to find 66².
- 27.Use a² − b² = (a + b)(a − b) to find 71² − 33².
- 28.Use a² − b² = (a + b)(a − b) to find 70² − 21².
- 29.Use (a + b)(a − b) = a² − b² to find 38 × 22.
- 30.Use (a − b)² = a² − 2ab + b² to find 26².
- 31.Use (a + b)(a − b) = a² − b² to find 37 × 23.
- 32.Use (a + b)² = a² + 2ab + b² to find 91².
- 33.If a + b = 19 and ab = 90, what is a² + b²?
- 34.Use (a + b)² = a² + 2ab + b² to find 25².
- 35.Find the value of x² + 2xy + y² when x = 11 and y = 1.
- 36.Use (a − b)² = a² − 2ab + b² to find 89².
- 37.Find the value of x² − 2xy + y² when x = 6 and y = 2.
- 38.Use (a − b)² = a² − 2ab + b² to find 12².
- 39.Use a² − b² = (a + b)(a − b) to find 90² − 46².
- 40.Use (a − b)² = a² − 2ab + b² to find 35².
Answer key
- 256
- 20
- 85
- 1849
- 145
- 7396
- 444
- 529
- 81
- 1519
- 7569
- 3969
- 15
- 545
- 13
- 8464
- 99
- 79
- 6273
- 484
- 5625
- 8075
- 1485
- 1936
- 2809
- 4356
- 3952
- 4459
- 836
- 676
- 851
- 8281
- 181
- 625
- 144
- 7921
- 16
- 144
- 5984
- 1225
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