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)(a − b) = a² − b² to find 26 × 14.
- 2.Find the value of x² − 2xy + y² when x = 14 and y = 10.
- 3.Use (a − b)² = a² − 2ab + b² to find 32².
- 4.If a − b = 1 and ab = 6, what is a² + b²?
- 5.Use (a − b)² = a² − 2ab + b² to find 81².
- 6.Use (a − b)² = a² − 2ab + b² to find 76².
- 7.Use (a + b)² = a² + 2ab + b² to find 88².
- 8.Use (a + b)² = a² + 2ab + b² to find 85².
- 9.Use (a − b)² = a² − 2ab + b² to find 21².
- 10.If a − b = 2 and ab = 3, what is a² + b²?
- 11.Find the value of x² − y² when x = 13 and y = 5.
- 12.Use a² − b² = (a + b)(a − b) to find 75² − 27².
- 13.If a − b = 8 and ab = 33, what is a² + b²?
- 14.Use (a + b)(a − b) = a² − b² to find 89 × 71.
- 15.Use a² − b² = (a + b)(a − b) to find 73² − 41².
- 16.Use a² − b² = (a + b)(a − b) to find 42² − 33².
- 17.Use a² − b² = (a + b)(a − b) to find 94² − 23².
- 18.Use a² − b² = (a + b)(a − b) to find 70² − 1².
- 19.Use (a − b)² = a² − 2ab + b² to find 59².
- 20.Use (a − b)² = a² − 2ab + b² to find 88².
- 21.Use (a − b)² = a² − 2ab + b² to find 26².
- 22.If a − b = 1 and ab = 2, what is a² + b²?
- 23.Use (a − b)² = a² − 2ab + b² to find 96².
- 24.Use a² − b² = (a + b)(a − b) to find 54² − 40².
- 25.Use a² − b² = (a + b)(a − b) to find 61² − 44².
- 26.Use (a − b)² = a² − 2ab + b² to find 78².
- 27.If a + b = 13 and ab = 36, what is a² + b²?
- 28.Find the value of x² − y² when x = 9 and y = 5.
- 29.If a + b = 6 and ab = 5, what is a² + b²?
- 30.Use (a + b)(a − b) = a² − b² to find 102 × 98.
- 31.Find the value of x² + 2xy + y² when x = 6 and y = 1.
- 32.Use a² − b² = (a + b)(a − b) to find 24² − 7².
- 33.Use (a + b)² = a² + 2ab + b² to find 82².
- 34.Use (a − b)² = a² − 2ab + b² to find 43².
- 35.Use (a − b)² = a² − 2ab + b² to find 95².
- 36.Use (a + b)(a − b) = a² − b² to find 95 × 85.
- 37.Find the value of x² + 2xy + y² when x = 3 and y = 2.
- 38.If a − b = 8 and ab = 20, what is a² + b²?
- 39.Use (a − b)² = a² − 2ab + b² to find 35².
- 40.Use (a − b)² = a² − 2ab + b² to find 75².
Answer key
- 364
- 16
- 1024
- 13
- 6561
- 5776
- 7744
- 7225
- 441
- 10
- 144
- 4896
- 130
- 6319
- 3648
- 675
- 8307
- 4899
- 3481
- 7744
- 676
- 5
- 9216
- 1316
- 1785
- 6084
- 97
- 56
- 26
- 9996
- 49
- 527
- 6724
- 1849
- 9025
- 8075
- 25
- 104
- 1225
- 5625
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