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 36² − 22².
- 2.Find the value of x² − 2xy + y² when x = 7 and y = 4.
- 3.Use (a + b)(a − b) = a² − b² to find 52 × 48.
- 4.Find the value of x² + 2xy + y² when x = 4 and y = 1.
- 5.Use (a + b)² = a² + 2ab + b² to find 88².
- 6.Use a² − b² = (a + b)(a − b) to find 20² − 4².
- 7.Use a² − b² = (a + b)(a − b) to find 52² − 24².
- 8.Use (a − b)² = a² − 2ab + b² to find 79².
- 9.Find the value of x² + 2xy + y² when x = 8 and y = 7.
- 10.Use (a + b)² = a² + 2ab + b² to find 78².
- 11.Find the value of x² + 2xy + y² when x = 9 and y = 5.
- 12.Use a² − b² = (a + b)(a − b) to find 84² − 19².
- 13.Use (a − b)² = a² − 2ab + b² to find 46².
- 14.Use (a + b)² = a² + 2ab + b² to find 29².
- 15.Find the value of x² − 2xy + y² when x = 9 and y = 4.
- 16.Use (a + b)(a − b) = a² − b² to find 99 × 81.
- 17.Find the value of x² − y² when x = 7 and y = 5.
- 18.Use (a + b)² = a² + 2ab + b² to find 101².
- 19.Use (a + b)(a − b) = a² − b² to find 101 × 99.
- 20.Use (a + b)² = a² + 2ab + b² to find 73².
- 21.Use (a − b)² = a² − 2ab + b² to find 94².
- 22.Find the value of x² − y² when x = 6 and y = 2.
- 23.Use (a + b)² = a² + 2ab + b² to find 27².
- 24.Use (a + b)² = a² + 2ab + b² to find 106².
- 25.If a − b = 3 and ab = 4, what is a² + b²?
- 26.Use (a + b)(a − b) = a² − b² to find 59 × 41.
- 27.Use (a + b)(a − b) = a² − b² to find 106 × 94.
- 28.Use (a + b)(a − b) = a² − b² to find 43 × 37.
- 29.Find the value of x² + 2xy + y² when x = 5 and y = 2.
- 30.Find the value of x² + 2xy + y² when x = 4 and y = 2.
- 31.Use (a − b)² = a² − 2ab + b² to find 99².
- 32.If a − b = 1 and ab = 6, what is a² + b²?
- 33.Find the value of x² + 2xy + y² when x = 6 and y = 2.
- 34.If a − b = 8 and ab = 33, what is a² + b²?
- 35.Find the value of x² − y² when x = 3 and y = 2.
- 36.Use (a − b)² = a² − 2ab + b² to find 48².
- 37.Use (a + b)² = a² + 2ab + b² to find 81².
- 38.Find the value of x² + 2xy + y² when x = 13 and y = 8.
- 39.Use (a + b)² = a² + 2ab + b² to find 85².
- 40.Use (a − b)² = a² − 2ab + b² to find 11².
Answer key
- 812
- 9
- 2496
- 25
- 7744
- 384
- 2128
- 6241
- 225
- 6084
- 196
- 6695
- 2116
- 841
- 25
- 8019
- 24
- 10201
- 9999
- 5329
- 8836
- 32
- 729
- 11236
- 17
- 2419
- 9964
- 1591
- 49
- 36
- 9801
- 13
- 64
- 130
- 5
- 2304
- 6561
- 441
- 7225
- 121
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