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 108 × 92.
- 2.If a + b = 14 and ab = 40, what is a² + b²?
- 3.Use (a − b)² = a² − 2ab + b² to find 89².
- 4.If a + b = 6 and ab = 8, what is a² + b²?
- 5.Use (a + b)² = a² + 2ab + b² to find 15².
- 6.Use (a − b)² = a² − 2ab + b² to find 71².
- 7.Use (a + b)(a − b) = a² − b² to find 38 × 22.
- 8.Use (a + b)² = a² + 2ab + b² to find 32².
- 9.If a − b = 2 and ab = 48, what is a² + b²?
- 10.Find the value of x² − 2xy + y² when x = 13 and y = 8.
- 11.If a − b = 1 and ab = 2, what is a² + b²?
- 12.Use (a + b)(a − b) = a² − b² to find 48 × 32.
- 13.Find the value of x² − 2xy + y² when x = 4 and y = 3.
- 14.If a + b = 7 and ab = 12, what is a² + b²?
- 15.Find the value of x² − y² when x = 12 and y = 8.
- 16.Use (a + b)² = a² + 2ab + b² to find 73².
- 17.Use a² − b² = (a + b)(a − b) to find 63² − 35².
- 18.If a + b = 3 and ab = 2, what is a² + b²?
- 19.Use (a + b)² = a² + 2ab + b² to find 23².
- 20.Use (a − b)² = a² − 2ab + b² to find 27².
- 21.Use (a + b)² = a² + 2ab + b² to find 55².
- 22.Use a² − b² = (a + b)(a − b) to find 24² − 5².
- 23.Find the value of x² + 2xy + y² when x = 11 and y = 3.
- 24.Use (a + b)² = a² + 2ab + b² to find 24².
- 25.Use (a + b)² = a² + 2ab + b² to find 69².
- 26.Use (a − b)² = a² − 2ab + b² to find 87².
- 27.Use (a + b)(a − b) = a² − b² to find 91 × 89.
- 28.Use (a + b)² = a² + 2ab + b² to find 47².
- 29.Use a² − b² = (a + b)(a − b) to find 60² − 48².
- 30.Use (a + b)(a − b) = a² − b² to find 67 × 53.
- 31.Use a² − b² = (a + b)(a − b) to find 45² − 11².
- 32.Use (a − b)² = a² − 2ab + b² to find 61².
- 33.Use (a + b)² = a² + 2ab + b² to find 109².
- 34.Use (a − b)² = a² − 2ab + b² to find 93².
- 35.If a + b = 17 and ab = 70, what is a² + b²?
- 36.Use (a + b)² = a² + 2ab + b² to find 75².
- 37.Use (a + b)² = a² + 2ab + b² to find 51².
- 38.Use a² − b² = (a + b)(a − b) to find 52² − 3².
- 39.Use (a − b)² = a² − 2ab + b² to find 97².
- 40.Use (a − b)² = a² − 2ab + b² to find 33².
Answer key
- 9936
- 116
- 7921
- 20
- 225
- 5041
- 836
- 1024
- 100
- 25
- 5
- 1536
- 1
- 25
- 80
- 5329
- 2744
- 5
- 529
- 729
- 3025
- 551
- 196
- 576
- 4761
- 7569
- 8099
- 2209
- 1296
- 3551
- 1904
- 3721
- 11881
- 8649
- 149
- 5625
- 2601
- 2695
- 9409
- 1089
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