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.Find the value of x² + 2xy + y² when x = 6 and y = 5.
- 2.Use (a + b)² = a² + 2ab + b² to find 66².
- 3.Find the value of x² + 2xy + y² when x = 9 and y = 3.
- 4.If a − b = 2 and ab = 3, what is a² + b²?
- 5.Use (a − b)² = a² − 2ab + b² to find 27².
- 6.If a + b = 4 and ab = 3, what is a² + b²?
- 7.If a − b = 1 and ab = 2, what is a² + b²?
- 8.Find the value of x² − y² when x = 14 and y = 7.
- 9.Find the value of x² − y² when x = 13 and y = 2.
- 10.Use a² − b² = (a + b)(a − b) to find 61² − 44².
- 11.Use (a + b)(a − b) = a² − b² to find 71 × 69.
- 12.Use (a − b)² = a² − 2ab + b² to find 61².
- 13.Use (a − b)² = a² − 2ab + b² to find 32².
- 14.Use (a − b)² = a² − 2ab + b² to find 57².
- 15.Use (a − b)² = a² − 2ab + b² to find 94².
- 16.Use (a + b)(a − b) = a² − b² to find 41 × 39.
- 17.Use (a + b)² = a² + 2ab + b² to find 33².
- 18.Use (a + b)² = a² + 2ab + b² to find 71².
- 19.Use (a − b)² = a² − 2ab + b² to find 69².
- 20.Use (a + b)² = a² + 2ab + b² to find 96².
- 21.Find the value of x² + 2xy + y² when x = 6 and y = 3.
- 22.Use (a + b)² = a² + 2ab + b² to find 16².
- 23.Use (a − b)² = a² − 2ab + b² to find 77².
- 24.Use a² − b² = (a + b)(a − b) to find 29² − 24².
- 25.Use (a + b)² = a² + 2ab + b² to find 81².
- 26.Use a² − b² = (a + b)(a − b) to find 82² − 22².
- 27.Use (a + b)(a − b) = a² − b² to find 35 × 25.
- 28.Use (a + b)² = a² + 2ab + b² to find 22².
- 29.Use (a + b)² = a² + 2ab + b² to find 18².
- 30.Use (a + b)² = a² + 2ab + b² to find 59².
- 31.If a + b = 10 and ab = 21, what is a² + b²?
- 32.Find the value of x² + 2xy + y² when x = 9 and y = 4.
- 33.Use a² − b² = (a + b)(a − b) to find 92² − 25².
- 34.If a + b = 7 and ab = 10, what is a² + b²?
- 35.Use (a + b)² = a² + 2ab + b² to find 93².
- 36.Use (a − b)² = a² − 2ab + b² to find 46².
- 37.Use (a + b)(a − b) = a² − b² to find 85 × 75.
- 38.Use a² − b² = (a + b)(a − b) to find 22² − 13².
- 39.Find the value of x² − y² when x = 15 and y = 14.
- 40.Use a² − b² = (a + b)(a − b) to find 80² − 65².
Answer key
- 121
- 4356
- 144
- 10
- 729
- 10
- 5
- 147
- 165
- 1785
- 4899
- 3721
- 1024
- 3249
- 8836
- 1599
- 1089
- 5041
- 4761
- 9216
- 81
- 256
- 5929
- 265
- 6561
- 6240
- 875
- 484
- 324
- 3481
- 58
- 169
- 7839
- 29
- 8649
- 2116
- 6375
- 315
- 29
- 2175
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