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 97² − 66².
- 2.Use (a − b)² = a² − 2ab + b² to find 88².
- 3.Use (a − b)² = a² − 2ab + b² to find 52².
- 4.If a + b = 10 and ab = 24, what is a² + b²?
- 5.Use (a + b)² = a² + 2ab + b² to find 26².
- 6.Use (a + b)² = a² + 2ab + b² to find 93².
- 7.Use (a + b)(a − b) = a² − b² to find 87 × 73.
- 8.Use (a − b)² = a² − 2ab + b² to find 17².
- 9.Use (a + b)² = a² + 2ab + b² to find 17².
- 10.If a − b = 2 and ab = 120, what is a² + b²?
- 11.Use a² − b² = (a + b)(a − b) to find 98² − 57².
- 12.Use a² − b² = (a + b)(a − b) to find 33² − 9².
- 13.Use (a + b)² = a² + 2ab + b² to find 22².
- 14.If a + b = 11 and ab = 10, what is a² + b²?
- 15.Use (a − b)² = a² − 2ab + b² to find 84².
- 16.If a − b = 7 and ab = 60, what is a² + b²?
- 17.Use (a + b)(a − b) = a² − b² to find 46 × 34.
- 18.Use (a − b)² = a² − 2ab + b² to find 32².
- 19.Use (a + b)² = a² + 2ab + b² to find 38².
- 20.If a − b = 3 and ab = 40, what is a² + b²?
- 21.Find the value of x² + 2xy + y² when x = 10 and y = 3.
- 22.Use (a − b)² = a² − 2ab + b² to find 67².
- 23.Find the value of x² − 2xy + y² when x = 5 and y = 3.
- 24.Use (a − b)² = a² − 2ab + b² to find 87².
- 25.Use (a − b)² = a² − 2ab + b² to find 28².
- 26.Use a² − b² = (a + b)(a − b) to find 93² − 22².
- 27.Find the value of x² + 2xy + y² when x = 11 and y = 8.
- 28.If a − b = 5 and ab = 36, what is a² + b²?
- 29.Find the value of x² + 2xy + y² when x = 6 and y = 5.
- 30.Use (a − b)² = a² − 2ab + b² to find 57².
- 31.Use (a + b)(a − b) = a² − b² to find 52 × 48.
- 32.If a + b = 20 and ab = 96, what is a² + b²?
- 33.Use (a + b)² = a² + 2ab + b² to find 77².
- 34.Use a² − b² = (a + b)(a − b) to find 47² − 12².
- 35.Use (a + b)² = a² + 2ab + b² to find 94².
- 36.Use (a + b)(a − b) = a² − b² to find 72 × 68.
- 37.Use (a − b)² = a² − 2ab + b² to find 13².
- 38.Find the value of x² + 2xy + y² when x = 12 and y = 7.
- 39.Use (a + b)² = a² + 2ab + b² to find 89².
- 40.Use (a + b)² = a² + 2ab + b² to find 16².
Answer key
- 5053
- 7744
- 2704
- 52
- 676
- 8649
- 6351
- 289
- 289
- 244
- 6355
- 1008
- 484
- 101
- 7056
- 169
- 1564
- 1024
- 1444
- 89
- 169
- 4489
- 4
- 7569
- 784
- 8165
- 361
- 97
- 121
- 3249
- 2496
- 208
- 5929
- 2065
- 8836
- 4896
- 169
- 361
- 7921
- 256
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