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 95².
- 2.Use (a − b)² = a² − 2ab + b² to find 73².
- 3.Use (a + b)² = a² + 2ab + b² to find 45².
- 4.If a − b = 3 and ab = 88, what is a² + b²?
- 5.Use (a − b)² = a² − 2ab + b² to find 21².
- 6.Use (a − b)² = a² − 2ab + b² to find 16².
- 7.Use a² − b² = (a + b)(a − b) to find 46² − 36².
- 8.Use (a + b)² = a² + 2ab + b² to find 98².
- 9.Use (a + b)² = a² + 2ab + b² to find 11².
- 10.Use a² − b² = (a + b)(a − b) to find 30² − 9².
- 11.Use (a + b)(a − b) = a² − b² to find 87 × 73.
- 12.If a + b = 12 and ab = 20, what is a² + b²?
- 13.If a + b = 17 and ab = 60, what is a² + b²?
- 14.Use (a + b)(a − b) = a² − b² to find 106 × 94.
- 15.Use (a − b)² = a² − 2ab + b² to find 38².
- 16.Use (a + b)² = a² + 2ab + b² to find 38².
- 17.Use (a + b)² = a² + 2ab + b² to find 25².
- 18.Use a² − b² = (a + b)(a − b) to find 22² − 16².
- 19.Use (a − b)² = a² − 2ab + b² to find 25².
- 20.Use (a + b)(a − b) = a² − b² to find 75 × 65.
- 21.Use (a + b)² = a² + 2ab + b² to find 15².
- 22.Use (a + b)(a − b) = a² − b² to find 89 × 71.
- 23.Use a² − b² = (a + b)(a − b) to find 77² − 34².
- 24.If a + b = 4 and ab = 3, what is a² + b²?
- 25.Find the value of x² − y² when x = 3 and y = 2.
- 26.Use (a + b)² = a² + 2ab + b² to find 78².
- 27.Use (a + b)(a − b) = a² − b² to find 46 × 34.
- 28.Use a² − b² = (a + b)(a − b) to find 23² − 8².
- 29.Use (a − b)² = a² − 2ab + b² to find 98².
- 30.Use (a − b)² = a² − 2ab + b² to find 24².
- 31.If a − b = 3 and ab = 4, what is a² + b²?
- 32.Use a² − b² = (a + b)(a − b) to find 76² − 35².
- 33.If a + b = 10 and ab = 9, what is a² + b²?
- 34.Find the value of x² − 2xy + y² when x = 7 and y = 5.
- 35.Use (a + b)² = a² + 2ab + b² to find 107².
- 36.Use (a + b)(a − b) = a² − b² to find 58 × 42.
- 37.If a − b = 5 and ab = 66, what is a² + b²?
- 38.Use (a − b)² = a² − 2ab + b² to find 39².
- 39.Use (a − b)² = a² − 2ab + b² to find 15².
- 40.If a − b = 1 and ab = 2, what is a² + b²?
Answer key
- 9025
- 5329
- 2025
- 185
- 441
- 256
- 820
- 9604
- 121
- 819
- 6351
- 104
- 169
- 9964
- 1444
- 1444
- 625
- 228
- 625
- 4875
- 225
- 6319
- 4773
- 10
- 5
- 6084
- 1564
- 465
- 9604
- 576
- 17
- 4551
- 82
- 4
- 11449
- 2436
- 157
- 1521
- 225
- 5
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