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 38².
- 2.Use (a + b)² = a² + 2ab + b² to find 94².
- 3.Use a² − b² = (a + b)(a − b) to find 23² − 6².
- 4.Use (a + b)(a − b) = a² − b² to find 103 × 97.
- 5.If a + b = 7 and ab = 12, what is a² + b²?
- 6.Use (a + b)(a − b) = a² − b² to find 66 × 54.
- 7.Use (a + b)² = a² + 2ab + b² to find 61².
- 8.Use a² − b² = (a + b)(a − b) to find 55² − 54².
- 9.Use a² − b² = (a + b)(a − b) to find 28² − 6².
- 10.Use a² − b² = (a + b)(a − b) to find 69² − 22².
- 11.Use (a + b)(a − b) = a² − b² to find 48 × 32.
- 12.Use (a + b)(a − b) = a² − b² to find 83 × 77.
- 13.Use a² − b² = (a + b)(a − b) to find 71² − 24².
- 14.Find the value of x² − 2xy + y² when x = 13 and y = 1.
- 15.Use a² − b² = (a + b)(a − b) to find 77² − 17².
- 16.Find the value of x² − y² when x = 10 and y = 9.
- 17.Use (a + b)(a − b) = a² − b² to find 25 × 15.
- 18.Use (a + b)² = a² + 2ab + b² to find 85².
- 19.Use (a − b)² = a² − 2ab + b² to find 15².
- 20.Use (a − b)² = a² − 2ab + b² to find 16².
- 21.Find the value of x² + 2xy + y² when x = 5 and y = 1.
- 22.If a + b = 5 and ab = 4, what is a² + b²?
- 23.If a + b = 14 and ab = 48, what is a² + b²?
- 24.Use (a + b)² = a² + 2ab + b² to find 68².
- 25.If a − b = 3 and ab = 28, what is a² + b²?
- 26.Use (a + b)² = a² + 2ab + b² to find 31².
- 27.Use (a − b)² = a² − 2ab + b² to find 87².
- 28.Find the value of x² + 2xy + y² when x = 7 and y = 1.
- 29.Use a² − b² = (a + b)(a − b) to find 82² − 53².
- 30.Use (a + b)(a − b) = a² − b² to find 73 × 67.
- 31.Use (a + b)² = a² + 2ab + b² to find 29².
- 32.Use (a − b)² = a² − 2ab + b² to find 48².
- 33.Use (a − b)² = a² − 2ab + b² to find 96².
- 34.If a + b = 6 and ab = 5, what is a² + b²?
- 35.Use a² − b² = (a + b)(a − b) to find 87² − 61².
- 36.Use (a + b)² = a² + 2ab + b² to find 19².
- 37.Use (a + b)² = a² + 2ab + b² to find 95².
- 38.If a − b = 2 and ab = 3, what is a² + b²?
- 39.Use (a − b)² = a² − 2ab + b² to find 72².
- 40.Find the value of x² + 2xy + y² when x = 13 and y = 2.
Answer key
- 1444
- 8836
- 493
- 9991
- 25
- 3564
- 3721
- 109
- 748
- 4277
- 1536
- 6391
- 4465
- 144
- 5640
- 19
- 375
- 7225
- 225
- 256
- 36
- 17
- 100
- 4624
- 65
- 961
- 7569
- 64
- 3915
- 4891
- 841
- 2304
- 9216
- 26
- 3848
- 361
- 9025
- 10
- 5184
- 225
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