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 40² − 1².
- 2.Use (a + b)² = a² + 2ab + b² to find 42².
- 3.Use (a + b)(a − b) = a² − b² to find 105 × 95.
- 4.If a + b = 7 and ab = 10, what is a² + b²?
- 5.Use (a + b)(a − b) = a² − b² to find 35 × 25.
- 6.If a − b = 3 and ab = 40, what is a² + b²?
- 7.If a − b = 2 and ab = 8, what is a² + b²?
- 8.Use (a − b)² = a² − 2ab + b² to find 19².
- 9.Use a² − b² = (a + b)(a − b) to find 35² − 28².
- 10.Find the value of x² + 2xy + y² when x = 15 and y = 2.
- 11.Use (a − b)² = a² − 2ab + b² to find 88².
- 12.Find the value of x² − y² when x = 13 and y = 9.
- 13.If a − b = 1 and ab = 12, what is a² + b²?
- 14.Use a² − b² = (a + b)(a − b) to find 98² − 80².
- 15.Use (a + b)(a − b) = a² − b² to find 94 × 86.
- 16.Use (a + b)² = a² + 2ab + b² to find 49².
- 17.Use (a + b)² = a² + 2ab + b² to find 24².
- 18.Find the value of x² − 2xy + y² when x = 7 and y = 1.
- 19.Use (a − b)² = a² − 2ab + b² to find 11².
- 20.Use (a − b)² = a² − 2ab + b² to find 67².
- 21.Use (a + b)(a − b) = a² − b² to find 42 × 38.
- 22.Use (a + b)(a − b) = a² − b² to find 106 × 94.
- 23.If a − b = 4 and ab = 12, what is a² + b²?
- 24.Use (a − b)² = a² − 2ab + b² to find 95².
- 25.If a − b = 1 and ab = 6, what is a² + b²?
- 26.Use (a + b)(a − b) = a² − b² to find 62 × 58.
- 27.Use (a + b)(a − b) = a² − b² to find 96 × 84.
- 28.Find the value of x² − 2xy + y² when x = 13 and y = 10.
- 29.If a − b = 3 and ab = 108, what is a² + b²?
- 30.Use (a − b)² = a² − 2ab + b² to find 93².
- 31.Use (a + b)² = a² + 2ab + b² to find 102².
- 32.Use a² − b² = (a + b)(a − b) to find 59² − 48².
- 33.Use (a − b)² = a² − 2ab + b² to find 52².
- 34.If a − b = 1 and ab = 110, what is a² + b²?
- 35.Use (a + b)(a − b) = a² − b² to find 55 × 45.
- 36.Use (a − b)² = a² − 2ab + b² to find 21².
- 37.Use a² − b² = (a + b)(a − b) to find 91² − 16².
- 38.Use (a − b)² = a² − 2ab + b² to find 92².
- 39.Use (a + b)² = a² + 2ab + b² to find 38².
- 40.Find the value of x² − 2xy + y² when x = 7 and y = 6.
Answer key
- 1599
- 1764
- 9975
- 29
- 875
- 89
- 20
- 361
- 441
- 289
- 7744
- 88
- 25
- 3204
- 8084
- 2401
- 576
- 36
- 121
- 4489
- 1596
- 9964
- 40
- 9025
- 13
- 3596
- 8064
- 9
- 225
- 8649
- 10404
- 1177
- 2704
- 221
- 2475
- 441
- 8025
- 8464
- 1444
- 1
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