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 = 12 and y = 10.
- 2.Use (a − b)² = a² − 2ab + b² to find 46².
- 3.Use (a + b)(a − b) = a² − b² to find 84 × 76.
- 4.Use (a + b)(a − b) = a² − b² to find 73 × 67.
- 5.Use (a + b)(a − b) = a² − b² to find 76 × 64.
- 6.Use (a + b)² = a² + 2ab + b² to find 94².
- 7.If a + b = 20 and ab = 99, what is a² + b²?
- 8.Find the value of x² − 2xy + y² when x = 6 and y = 5.
- 9.Find the value of x² − 2xy + y² when x = 8 and y = 1.
- 10.Use (a − b)² = a² − 2ab + b² to find 28².
- 11.Use (a + b)² = a² + 2ab + b² to find 107².
- 12.Use (a − b)² = a² − 2ab + b² to find 49².
- 13.Use (a − b)² = a² − 2ab + b² to find 24².
- 14.Use (a + b)² = a² + 2ab + b² to find 55².
- 15.Use (a + b)² = a² + 2ab + b² to find 27².
- 16.If a + b = 5 and ab = 4, what is a² + b²?
- 17.Use (a + b)² = a² + 2ab + b² to find 32².
- 18.Use (a − b)² = a² − 2ab + b² to find 27².
- 19.Use (a + b)² = a² + 2ab + b² to find 16².
- 20.If a + b = 7 and ab = 10, what is a² + b²?
- 21.Use (a + b)(a − b) = a² − b² to find 95 × 85.
- 22.Use (a − b)² = a² − 2ab + b² to find 37².
- 23.Use (a + b)² = a² + 2ab + b² to find 105².
- 24.Use (a + b)² = a² + 2ab + b² to find 97².
- 25.Use a² − b² = (a + b)(a − b) to find 25² − 12².
- 26.Use (a + b)(a − b) = a² − b² to find 47 × 33.
- 27.Use (a − b)² = a² − 2ab + b² to find 52².
- 28.Use (a − b)² = a² − 2ab + b² to find 48².
- 29.Find the value of x² + 2xy + y² when x = 10 and y = 1.
- 30.Find the value of x² + 2xy + y² when x = 14 and y = 4.
- 31.Find the value of x² − 2xy + y² when x = 11 and y = 2.
- 32.If a + b = 3 and ab = 2, what is a² + b²?
- 33.Find the value of x² − 2xy + y² when x = 12 and y = 11.
- 34.Use (a + b)² = a² + 2ab + b² to find 34².
- 35.Use (a + b)² = a² + 2ab + b² to find 92².
- 36.If a + b = 16 and ab = 60, what is a² + b²?
- 37.Use (a + b)² = a² + 2ab + b² to find 61².
- 38.Use (a − b)² = a² − 2ab + b² to find 13².
- 39.Use (a + b)² = a² + 2ab + b² to find 18².
- 40.Use (a − b)² = a² − 2ab + b² to find 33².
Answer key
- 484
- 2116
- 6384
- 4891
- 4864
- 8836
- 202
- 1
- 49
- 784
- 11449
- 2401
- 576
- 3025
- 729
- 17
- 1024
- 729
- 256
- 29
- 8075
- 1369
- 11025
- 9409
- 481
- 1551
- 2704
- 2304
- 121
- 324
- 81
- 5
- 1
- 1156
- 8464
- 136
- 3721
- 169
- 324
- 1089
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