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.
NameDateTime takenScore ___ / 40
- 1.Use (a + b)² = a² + 2ab + b² to find 57².
- 2.Use (a − b)² = a² − 2ab + b² to find 43².
- 3.Use (a + b)(a − b) = a² − b² to find 92 × 88.
- 4.Use (a + b)(a − b) = a² − b² to find 53 × 47.
- 5.Use (a − b)² = a² − 2ab + b² to find 99².
- 6.Use (a + b)² = a² + 2ab + b² to find 56².
- 7.Use a² − b² = (a + b)(a − b) to find 37² − 31².
- 8.Find the value of x² − 2xy + y² when x = 15 and y = 1.
- 9.Use a² − b² = (a + b)(a − b) to find 84² − 72².
- 10.Use a² − b² = (a + b)(a − b) to find 94² − 81².
- 11.Use (a + b)² = a² + 2ab + b² to find 91².
- 12.Use a² − b² = (a + b)(a − b) to find 81² − 69².
- 13.Use (a − b)² = a² − 2ab + b² to find 33².
- 14.Use a² − b² = (a + b)(a − b) to find 31² − 6².
- 15.Use (a − b)² = a² − 2ab + b² to find 61².
- 16.Find the value of x² − y² when x = 5 and y = 3.
- 17.Use a² − b² = (a + b)(a − b) to find 56² − 44².
- 18.If a + b = 3 and ab = 2, what is a² + b²?
- 19.Use (a + b)² = a² + 2ab + b² to find 13².
- 20.Use (a + b)(a − b) = a² − b² to find 99 × 81.
- 21.If a − b = 2 and ab = 63, what is a² + b²?
- 22.Use a² − b² = (a + b)(a − b) to find 24² − 3².
- 23.Use (a − b)² = a² − 2ab + b² to find 89².
- 24.If a − b = 4 and ab = 5, what is a² + b²?
- 25.Use (a + b)(a − b) = a² − b² to find 93 × 87.
- 26.Find the value of x² + 2xy + y² when x = 11 and y = 6.
- 27.Use (a − b)² = a² − 2ab + b² to find 79².
- 28.Use (a + b)(a − b) = a² − b² to find 35 × 25.
- 29.Find the value of x² − 2xy + y² when x = 12 and y = 1.
- 30.Use a² − b² = (a + b)(a − b) to find 20² − 17².
- 31.Find the value of x² + 2xy + y² when x = 10 and y = 2.
- 32.Use (a + b)(a − b) = a² − b² to find 103 × 97.
- 33.Use (a + b)² = a² + 2ab + b² to find 28².
- 34.Use (a + b)² = a² + 2ab + b² to find 37².
- 35.Use (a − b)² = a² − 2ab + b² to find 96².
- 36.Use a² − b² = (a + b)(a − b) to find 29² − 2².
- 37.Use (a − b)² = a² − 2ab + b² to find 45².
- 38.Use (a + b)² = a² + 2ab + b² to find 95².
- 39.Use a² − b² = (a + b)(a − b) to find 75² − 59².
- 40.If a + b = 15 and ab = 56, what is a² + b²?
Answer key
- 3249
- 1849
- 8096
- 2491
- 9801
- 3136
- 408
- 196
- 1872
- 2275
- 8281
- 1800
- 1089
- 925
- 3721
- 16
- 1200
- 5
- 169
- 8019
- 130
- 567
- 7921
- 26
- 8091
- 289
- 6241
- 875
- 121
- 111
- 144
- 9991
- 784
- 1369
- 9216
- 837
- 2025
- 9025
- 2144
- 113
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