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 17².
- 2.Use (a − b)² = a² − 2ab + b² to find 75².
- 3.Use (a + b)(a − b) = a² − b² to find 58 × 42.
- 4.Use (a + b)² = a² + 2ab + b² to find 46².
- 5.Use a² − b² = (a + b)(a − b) to find 25² − 6².
- 6.Use (a + b)² = a² + 2ab + b² to find 23².
- 7.Use (a + b)² = a² + 2ab + b² to find 94².
- 8.Use (a − b)² = a² − 2ab + b² to find 36².
- 9.Use (a + b)² = a² + 2ab + b² to find 78².
- 10.Use (a + b)(a − b) = a² − b² to find 104 × 96.
- 11.Use a² − b² = (a + b)(a − b) to find 46² − 13².
- 12.Use a² − b² = (a + b)(a − b) to find 47² − 43².
- 13.Use (a − b)² = a² − 2ab + b² to find 77².
- 14.Find the value of x² − 2xy + y² when x = 12 and y = 1.
- 15.Find the value of x² + 2xy + y² when x = 4 and y = 3.
- 16.If a − b = 5 and ab = 6, what is a² + b²?
- 17.If a + b = 7 and ab = 12, what is a² + b²?
- 18.Use a² − b² = (a + b)(a − b) to find 47² − 44².
- 19.Use a² − b² = (a + b)(a − b) to find 73² − 1².
- 20.Find the value of x² + 2xy + y² when x = 7 and y = 5.
- 21.Use (a + b)² = a² + 2ab + b² to find 61².
- 22.Use (a + b)² = a² + 2ab + b² to find 92².
- 23.If a + b = 6 and ab = 8, what is a² + b²?
- 24.Use (a + b)(a − b) = a² − b² to find 62 × 58.
- 25.Use (a − b)² = a² − 2ab + b² to find 22².
- 26.Use (a + b)(a − b) = a² − b² to find 42 × 38.
- 27.Use (a − b)² = a² − 2ab + b² to find 48².
- 28.Use a² − b² = (a + b)(a − b) to find 75² − 34².
- 29.If a − b = 1 and ab = 20, what is a² + b²?
- 30.Find the value of x² + 2xy + y² when x = 3 and y = 1.
- 31.Use a² − b² = (a + b)(a − b) to find 79² − 34².
- 32.Use a² − b² = (a + b)(a − b) to find 53² − 15².
- 33.Use (a + b)(a − b) = a² − b² to find 73 × 67.
- 34.Use (a + b)² = a² + 2ab + b² to find 18².
- 35.If a + b = 3 and ab = 2, what is a² + b²?
- 36.Find the value of x² − 2xy + y² when x = 7 and y = 1.
- 37.Use (a + b)² = a² + 2ab + b² to find 51².
- 38.Use (a + b)(a − b) = a² − b² to find 65 × 55.
- 39.Use (a + b)² = a² + 2ab + b² to find 107².
- 40.Use (a − b)² = a² − 2ab + b² to find 28².
Answer key
- 289
- 5625
- 2436
- 2116
- 589
- 529
- 8836
- 1296
- 6084
- 9984
- 1947
- 360
- 5929
- 121
- 49
- 37
- 25
- 273
- 5328
- 144
- 3721
- 8464
- 20
- 3596
- 484
- 1596
- 2304
- 4469
- 41
- 16
- 5085
- 2584
- 4891
- 324
- 5
- 36
- 2601
- 3575
- 11449
- 784
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