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 23².
- 2.Use (a + b)² = a² + 2ab + b² to find 31².
- 3.Use (a − b)² = a² − 2ab + b² to find 81².
- 4.Use a² − b² = (a + b)(a − b) to find 56² − 46².
- 5.Use a² − b² = (a + b)(a − b) to find 37² − 3².
- 6.Use (a + b)² = a² + 2ab + b² to find 19².
- 7.Use (a − b)² = a² − 2ab + b² to find 12².
- 8.Use (a + b)(a − b) = a² − b² to find 64 × 56.
- 9.Use a² − b² = (a + b)(a − b) to find 50² − 39².
- 10.Find the value of x² + 2xy + y² when x = 13 and y = 11.
- 11.If a + b = 17 and ab = 66, what is a² + b²?
- 12.Use (a − b)² = a² − 2ab + b² to find 95².
- 13.Use (a + b)(a − b) = a² − b² to find 58 × 42.
- 14.Use a² − b² = (a + b)(a − b) to find 31² − 30².
- 15.Use (a − b)² = a² − 2ab + b² to find 44².
- 16.Use (a + b)² = a² + 2ab + b² to find 73².
- 17.Use (a + b)² = a² + 2ab + b² to find 49².
- 18.Find the value of x² − y² when x = 9 and y = 3.
- 19.Use (a + b)² = a² + 2ab + b² to find 14².
- 20.Use (a + b)(a − b) = a² − b² to find 88 × 72.
- 21.Use (a + b)² = a² + 2ab + b² to find 13².
- 22.Use (a + b)² = a² + 2ab + b² to find 84².
- 23.Use a² − b² = (a + b)(a − b) to find 72² − 1².
- 24.Find the value of x² − 2xy + y² when x = 13 and y = 1.
- 25.Use a² − b² = (a + b)(a − b) to find 35² − 21².
- 26.If a + b = 13 and ab = 40, what is a² + b²?
- 27.If a − b = 2 and ab = 8, what is a² + b²?
- 28.Use a² − b² = (a + b)(a − b) to find 58² − 2².
- 29.Find the value of x² − 2xy + y² when x = 4 and y = 2.
- 30.Use a² − b² = (a + b)(a − b) to find 96² − 88².
- 31.Use a² − b² = (a + b)(a − b) to find 21² − 4².
- 32.Use (a + b)(a − b) = a² − b² to find 45 × 35.
- 33.Use (a + b)² = a² + 2ab + b² to find 78².
- 34.Find the value of x² + 2xy + y² when x = 7 and y = 6.
- 35.Use (a − b)² = a² − 2ab + b² to find 34².
- 36.Use (a + b)(a − b) = a² − b² to find 29 × 11.
- 37.Use (a − b)² = a² − 2ab + b² to find 77².
- 38.Use (a + b)² = a² + 2ab + b² to find 36².
- 39.Use (a + b)² = a² + 2ab + b² to find 108².
- 40.Find the value of x² − 2xy + y² when x = 6 and y = 2.
Answer key
- 529
- 961
- 6561
- 1020
- 1360
- 361
- 144
- 3584
- 979
- 576
- 157
- 9025
- 2436
- 61
- 1936
- 5329
- 2401
- 72
- 196
- 6336
- 169
- 7056
- 5183
- 144
- 784
- 89
- 20
- 3360
- 4
- 1472
- 425
- 1575
- 6084
- 169
- 1156
- 319
- 5929
- 1296
- 11664
- 16
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