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 67 × 53.
- 2.Use (a − b)² = a² − 2ab + b² to find 35².
- 3.Use (a − b)² = a² − 2ab + b² to find 18².
- 4.Use (a + b)(a − b) = a² − b² to find 47 × 33.
- 5.If a + b = 3 and ab = 2, what is a² + b²?
- 6.If a − b = 2 and ab = 8, what is a² + b²?
- 7.If a + b = 4 and ab = 3, what is a² + b²?
- 8.Find the value of x² − y² when x = 6 and y = 1.
- 9.Use a² − b² = (a + b)(a − b) to find 54² − 44².
- 10.Use (a + b)(a − b) = a² − b² to find 44 × 36.
- 11.Use (a − b)² = a² − 2ab + b² to find 27².
- 12.Find the value of x² + 2xy + y² when x = 15 and y = 3.
- 13.Use (a − b)² = a² − 2ab + b² to find 94².
- 14.Use (a − b)² = a² − 2ab + b² to find 95².
- 15.Use (a − b)² = a² − 2ab + b² to find 16².
- 16.Use (a + b)(a − b) = a² − b² to find 32 × 28.
- 17.Find the value of x² − 2xy + y² when x = 12 and y = 6.
- 18.Find the value of x² + 2xy + y² when x = 10 and y = 2.
- 19.Use (a + b)(a − b) = a² − b² to find 63 × 57.
- 20.Find the value of x² + 2xy + y² when x = 11 and y = 7.
- 21.If a − b = 1 and ab = 2, what is a² + b²?
- 22.Use (a − b)² = a² − 2ab + b² to find 57².
- 23.Use (a − b)² = a² − 2ab + b² to find 45².
- 24.Use (a + b)² = a² + 2ab + b² to find 33².
- 25.Use (a − b)² = a² − 2ab + b² to find 11².
- 26.Use (a − b)² = a² − 2ab + b² to find 39².
- 27.Use (a + b)(a − b) = a² − b² to find 91 × 89.
- 28.Use (a + b)² = a² + 2ab + b² to find 102².
- 29.Use (a + b)² = a² + 2ab + b² to find 14².
- 30.Use (a + b)(a − b) = a² − b² to find 33 × 27.
- 31.Use a² − b² = (a + b)(a − b) to find 58² − 16².
- 32.Use (a + b)(a − b) = a² − b² to find 43 × 37.
- 33.Use (a + b)(a − b) = a² − b² to find 23 × 17.
- 34.Use (a + b)² = a² + 2ab + b² to find 74².
- 35.Use a² − b² = (a + b)(a − b) to find 59² − 28².
- 36.Use a² − b² = (a + b)(a − b) to find 81² − 59².
- 37.Use (a − b)² = a² − 2ab + b² to find 84².
- 38.Use a² − b² = (a + b)(a − b) to find 88² − 13².
- 39.If a − b = 7 and ab = 8, what is a² + b²?
- 40.Use a² − b² = (a + b)(a − b) to find 41² − 1².
Answer key
- 3551
- 1225
- 324
- 1551
- 5
- 20
- 10
- 35
- 980
- 1584
- 729
- 324
- 8836
- 9025
- 256
- 896
- 36
- 144
- 3591
- 324
- 5
- 3249
- 2025
- 1089
- 121
- 1521
- 8099
- 10404
- 196
- 891
- 3108
- 1591
- 391
- 5476
- 2697
- 3080
- 7056
- 7575
- 65
- 1680
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