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 19².
- 2.Use (a − b)² = a² − 2ab + b² to find 64².
- 3.Use (a + b)² = a² + 2ab + b² to find 61².
- 4.Use (a + b)(a − b) = a² − b² to find 84 × 76.
- 5.Use (a + b)² = a² + 2ab + b² to find 82².
- 6.Use (a − b)² = a² − 2ab + b² to find 96².
- 7.Use a² − b² = (a + b)(a − b) to find 82² − 77².
- 8.Use (a − b)² = a² − 2ab + b² to find 71².
- 9.Use (a − b)² = a² − 2ab + b² to find 48².
- 10.Find the value of x² − y² when x = 4 and y = 3.
- 11.Use (a − b)² = a² − 2ab + b² to find 87².
- 12.Use (a + b)(a − b) = a² − b² to find 65 × 55.
- 13.Use a² − b² = (a + b)(a − b) to find 28² − 26².
- 14.Use a² − b² = (a + b)(a − b) to find 32² − 24².
- 15.Use (a − b)² = a² − 2ab + b² to find 93².
- 16.Use (a + b)² = a² + 2ab + b² to find 16².
- 17.Use a² − b² = (a + b)(a − b) to find 78² − 35².
- 18.If a − b = 6 and ab = 7, what is a² + b²?
- 19.If a − b = 4 and ab = 45, what is a² + b²?
- 20.Use (a − b)² = a² − 2ab + b² to find 53².
- 21.Find the value of x² − y² when x = 11 and y = 2.
- 22.If a + b = 15 and ab = 36, what is a² + b²?
- 23.Use (a − b)² = a² − 2ab + b² to find 27².
- 24.Use (a + b)(a − b) = a² − b² to find 47 × 33.
- 25.Use (a − b)² = a² − 2ab + b² to find 12².
- 26.Use (a − b)² = a² − 2ab + b² to find 91².
- 27.Use (a + b)² = a² + 2ab + b² to find 25².
- 28.Use (a + b)² = a² + 2ab + b² to find 81².
- 29.Use (a + b)² = a² + 2ab + b² to find 17².
- 30.Use (a + b)² = a² + 2ab + b² to find 14².
- 31.If a + b = 3 and ab = 2, what is a² + b²?
- 32.Use a² − b² = (a + b)(a − b) to find 24² − 2².
- 33.Use (a + b)² = a² + 2ab + b² to find 23².
- 34.Use (a − b)² = a² − 2ab + b² to find 39².
- 35.If a + b = 17 and ab = 72, what is a² + b²?
- 36.Use (a − b)² = a² − 2ab + b² to find 16².
- 37.Find the value of x² − y² when x = 5 and y = 1.
- 38.Find the value of x² + 2xy + y² when x = 11 and y = 1.
- 39.If a − b = 3 and ab = 4, what is a² + b²?
- 40.Use (a − b)² = a² − 2ab + b² to find 67².
Answer key
- 361
- 4096
- 3721
- 6384
- 6724
- 9216
- 795
- 5041
- 2304
- 7
- 7569
- 3575
- 108
- 448
- 8649
- 256
- 4859
- 50
- 106
- 2809
- 117
- 153
- 729
- 1551
- 144
- 8281
- 625
- 6561
- 289
- 196
- 5
- 572
- 529
- 1521
- 145
- 256
- 24
- 144
- 17
- 4489
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