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)² = a² − 2ab + b² to find 46².
- 2.Use (a + b)² = a² + 2ab + b² to find 105².
- 3.Use a² − b² = (a + b)(a − b) to find 43² − 6².
- 4.Use (a + b)(a − b) = a² − b² to find 78 × 62.
- 5.If a + b = 22 and ab = 120, what is a² + b²?
- 6.If a + b = 18 and ab = 80, what is a² + b²?
- 7.Use (a − b)² = a² − 2ab + b² to find 56².
- 8.If a − b = 1 and ab = 6, what is a² + b²?
- 9.Find the value of x² − y² when x = 6 and y = 4.
- 10.Use (a − b)² = a² − 2ab + b² to find 49².
- 11.Use (a − b)² = a² − 2ab + b² to find 27².
- 12.Use (a − b)² = a² − 2ab + b² to find 43².
- 13.Use (a − b)² = a² − 2ab + b² to find 69².
- 14.Use (a − b)² = a² − 2ab + b² to find 58².
- 15.Use (a + b)(a − b) = a² − b² to find 28 × 12.
- 16.Find the value of x² − y² when x = 13 and y = 3.
- 17.Use (a + b)² = a² + 2ab + b² to find 75².
- 18.Use (a − b)² = a² − 2ab + b² to find 67².
- 19.Use (a + b)² = a² + 2ab + b² to find 26².
- 20.Use (a + b)² = a² + 2ab + b² to find 32².
- 21.Use a² − b² = (a + b)(a − b) to find 99² − 34².
- 22.Find the value of x² − y² when x = 9 and y = 5.
- 23.Use (a + b)² = a² + 2ab + b² to find 48².
- 24.Use (a + b)² = a² + 2ab + b² to find 65².
- 25.Use (a + b)² = a² + 2ab + b² to find 19².
- 26.Use (a + b)(a − b) = a² − b² to find 91 × 89.
- 27.Use a² − b² = (a + b)(a − b) to find 38² − 12².
- 28.Use a² − b² = (a + b)(a − b) to find 86² − 23².
- 29.If a − b = 1 and ab = 2, what is a² + b²?
- 30.Use a² − b² = (a + b)(a − b) to find 70² − 58².
- 31.If a − b = 6 and ab = 16, what is a² + b²?
- 32.Use (a + b)² = a² + 2ab + b² to find 95².
- 33.Use (a + b)² = a² + 2ab + b² to find 12².
- 34.If a − b = 2 and ab = 3, what is a² + b²?
- 35.Find the value of x² + 2xy + y² when x = 13 and y = 4.
- 36.Use (a + b)² = a² + 2ab + b² to find 25².
- 37.Use (a − b)² = a² − 2ab + b² to find 57².
- 38.If a + b = 15 and ab = 50, what is a² + b²?
- 39.Use (a + b)² = a² + 2ab + b² to find 37².
- 40.Use (a − b)² = a² − 2ab + b² to find 53².
Answer key
- 2116
- 11025
- 1813
- 4836
- 244
- 164
- 3136
- 13
- 20
- 2401
- 729
- 1849
- 4761
- 3364
- 336
- 160
- 5625
- 4489
- 676
- 1024
- 8645
- 56
- 2304
- 4225
- 361
- 8099
- 1300
- 6867
- 5
- 1536
- 68
- 9025
- 144
- 10
- 289
- 625
- 3249
- 125
- 1369
- 2809
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