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.If a + b = 12 and ab = 27, what is a² + b²?
- 2.Use (a − b)² = a² − 2ab + b² to find 25².
- 3.Use a² − b² = (a + b)(a − b) to find 21² − 11².
- 4.Use (a + b)(a − b) = a² − b² to find 44 × 36.
- 5.Use (a + b)(a − b) = a² − b² to find 28 × 12.
- 6.Use (a − b)² = a² − 2ab + b² to find 61².
- 7.Use (a + b)² = a² + 2ab + b² to find 34².
- 8.Use (a + b)² = a² + 2ab + b² to find 73².
- 9.Use (a − b)² = a² − 2ab + b² to find 21².
- 10.Use (a − b)² = a² − 2ab + b² to find 98².
- 11.Use (a + b)² = a² + 2ab + b² to find 52².
- 12.Use (a + b)² = a² + 2ab + b² to find 108².
- 13.If a + b = 14 and ab = 24, what is a² + b²?
- 14.Use (a − b)² = a² − 2ab + b² to find 23².
- 15.Find the value of x² − y² when x = 8 and y = 7.
- 16.Use (a − b)² = a² − 2ab + b² to find 91².
- 17.If a − b = 1 and ab = 2, what is a² + b²?
- 18.Use (a + b)(a − b) = a² − b² to find 26 × 14.
- 19.Find the value of x² − 2xy + y² when x = 12 and y = 11.
- 20.Find the value of x² − 2xy + y² when x = 7 and y = 1.
- 21.Use (a + b)(a − b) = a² − b² to find 29 × 11.
- 22.Use (a + b)(a − b) = a² − b² to find 99 × 81.
- 23.Use (a + b)² = a² + 2ab + b² to find 74².
- 24.If a − b = 2 and ab = 35, what is a² + b²?
- 25.Find the value of x² − y² when x = 4 and y = 1.
- 26.If a − b = 9 and ab = 10, what is a² + b²?
- 27.Use (a + b)² = a² + 2ab + b² to find 45².
- 28.Use (a − b)² = a² − 2ab + b² to find 66².
- 29.If a + b = 10 and ab = 24, what is a² + b²?
- 30.Use (a − b)² = a² − 2ab + b² to find 41².
- 31.Find the value of x² + 2xy + y² when x = 15 and y = 8.
- 32.Use a² − b² = (a + b)(a − b) to find 53² − 6².
- 33.If a − b = 5 and ab = 36, what is a² + b²?
- 34.Use (a + b)² = a² + 2ab + b² to find 54².
- 35.Find the value of x² + 2xy + y² when x = 3 and y = 2.
- 36.Use (a + b)(a − b) = a² − b² to find 59 × 41.
- 37.Use (a + b)² = a² + 2ab + b² to find 39².
- 38.Use (a + b)(a − b) = a² − b² to find 92 × 88.
- 39.Find the value of x² + 2xy + y² when x = 4 and y = 1.
- 40.Use (a − b)² = a² − 2ab + b² to find 62².
Answer key
- 90
- 625
- 320
- 1584
- 336
- 3721
- 1156
- 5329
- 441
- 9604
- 2704
- 11664
- 148
- 529
- 15
- 8281
- 5
- 364
- 1
- 36
- 319
- 8019
- 5476
- 74
- 15
- 101
- 2025
- 4356
- 52
- 1681
- 529
- 2773
- 97
- 2916
- 25
- 2419
- 1521
- 8096
- 25
- 3844
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