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 = 4 and y = 2.
- 2.Use (a − b)² = a² − 2ab + b² to find 35².
- 3.Use (a + b)² = a² + 2ab + b² to find 54².
- 4.Use (a + b)² = a² + 2ab + b² to find 36².
- 5.Use (a + b)² = a² + 2ab + b² to find 34².
- 6.If a + b = 10 and ab = 9, what is a² + b²?
- 7.Use (a + b)² = a² + 2ab + b² to find 27².
- 8.Use (a + b)² = a² + 2ab + b² to find 33².
- 9.Use (a + b)(a − b) = a² − b² to find 53 × 47.
- 10.Find the value of x² − 2xy + y² when x = 13 and y = 4.
- 11.If a − b = 4 and ab = 32, what is a² + b²?
- 12.Use (a − b)² = a² − 2ab + b² to find 24².
- 13.If a − b = 5 and ab = 36, what is a² + b²?
- 14.Use a² − b² = (a + b)(a − b) to find 37² − 35².
- 15.Use (a − b)² = a² − 2ab + b² to find 33².
- 16.Find the value of x² − 2xy + y² when x = 5 and y = 2.
- 17.Use (a + b)² = a² + 2ab + b² to find 94².
- 18.Use a² − b² = (a + b)(a − b) to find 84² − 27².
- 19.Use (a + b)² = a² + 2ab + b² to find 18².
- 20.Use a² − b² = (a + b)(a − b) to find 72² − 1².
- 21.Use (a + b)(a − b) = a² − b² to find 93 × 87.
- 22.Find the value of x² − 2xy + y² when x = 3 and y = 1.
- 23.Use a² − b² = (a + b)(a − b) to find 99² − 4².
- 24.Use (a + b)² = a² + 2ab + b² to find 65².
- 25.Use (a + b)(a − b) = a² − b² to find 76 × 64.
- 26.Use a² − b² = (a + b)(a − b) to find 73² − 3².
- 27.Find the value of x² − y² when x = 9 and y = 2.
- 28.Use (a + b)² = a² + 2ab + b² to find 17².
- 29.Use (a + b)(a − b) = a² − b² to find 52 × 48.
- 30.Use (a + b)(a − b) = a² − b² to find 62 × 58.
- 31.If a − b = 2 and ab = 3, what is a² + b²?
- 32.Use (a + b)² = a² + 2ab + b² to find 15².
- 33.If a − b = 5 and ab = 24, what is a² + b²?
- 34.If a + b = 16 and ab = 55, what is a² + b²?
- 35.Find the value of x² + 2xy + y² when x = 10 and y = 5.
- 36.Use a² − b² = (a + b)(a − b) to find 90² − 72².
- 37.Use (a − b)² = a² − 2ab + b² to find 74².
- 38.Use (a + b)(a − b) = a² − b² to find 42 × 38.
- 39.Use (a + b)² = a² + 2ab + b² to find 63².
- 40.Use (a − b)² = a² − 2ab + b² to find 34².
Answer key
- 36
- 1225
- 2916
- 1296
- 1156
- 82
- 729
- 1089
- 2491
- 81
- 80
- 576
- 97
- 144
- 1089
- 9
- 8836
- 6327
- 324
- 5183
- 8091
- 4
- 9785
- 4225
- 4864
- 5320
- 77
- 289
- 2496
- 3596
- 10
- 225
- 73
- 146
- 225
- 2916
- 5476
- 1596
- 3969
- 1156
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