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 35².
- 2.Use (a − b)² = a² − 2ab + b² to find 41².
- 3.Use (a + b)² = a² + 2ab + b² to find 13².
- 4.Use (a − b)² = a² − 2ab + b² to find 71².
- 5.Use (a − b)² = a² − 2ab + b² to find 21².
- 6.If a − b = 9 and ab = 36, what is a² + b²?
- 7.Use (a + b)² = a² + 2ab + b² to find 17².
- 8.If a + b = 6 and ab = 8, what is a² + b²?
- 9.Use a² − b² = (a + b)(a − b) to find 86² − 65².
- 10.Find the value of x² − y² when x = 10 and y = 8.
- 11.Use (a + b)² = a² + 2ab + b² to find 103².
- 12.Find the value of x² + 2xy + y² when x = 8 and y = 6.
- 13.Find the value of x² + 2xy + y² when x = 13 and y = 9.
- 14.Use (a + b)(a − b) = a² − b² to find 41 × 39.
- 15.If a − b = 4 and ab = 21, what is a² + b²?
- 16.Use a² − b² = (a + b)(a − b) to find 79² − 52².
- 17.Use (a + b)² = a² + 2ab + b² to find 66².
- 18.Use (a − b)² = a² − 2ab + b² to find 88².
- 19.Use (a + b)(a − b) = a² − b² to find 82 × 78.
- 20.Use (a + b)² = a² + 2ab + b² to find 61².
- 21.Use (a − b)² = a² − 2ab + b² to find 77².
- 22.Use (a + b)² = a² + 2ab + b² to find 96².
- 23.Use a² − b² = (a + b)(a − b) to find 36² − 7².
- 24.Use (a + b)(a − b) = a² − b² to find 69 × 51.
- 25.Use (a − b)² = a² − 2ab + b² to find 34².
- 26.Use a² − b² = (a + b)(a − b) to find 87² − 26².
- 27.Use (a − b)² = a² − 2ab + b² to find 57².
- 28.If a − b = 7 and ab = 44, what is a² + b²?
- 29.Find the value of x² − 2xy + y² when x = 13 and y = 9.
- 30.Use a² − b² = (a + b)(a − b) to find 72² − 9².
- 31.Use (a + b)(a − b) = a² − b² to find 26 × 14.
- 32.Use (a + b)² = a² + 2ab + b² to find 109².
- 33.Find the value of x² + 2xy + y² when x = 11 and y = 6.
- 34.If a − b = 4 and ab = 32, what is a² + b²?
- 35.Use (a + b)² = a² + 2ab + b² to find 27².
- 36.Use (a − b)² = a² − 2ab + b² to find 94².
- 37.Use (a − b)² = a² − 2ab + b² to find 17².
- 38.Use (a − b)² = a² − 2ab + b² to find 47².
- 39.Use a² − b² = (a + b)(a − b) to find 32² − 2².
- 40.Use (a + b)² = a² + 2ab + b² to find 12².
Answer key
- 1225
- 1681
- 169
- 5041
- 441
- 153
- 289
- 20
- 3171
- 36
- 10609
- 196
- 484
- 1599
- 58
- 3537
- 4356
- 7744
- 6396
- 3721
- 5929
- 9216
- 1247
- 3519
- 1156
- 6893
- 3249
- 137
- 16
- 5103
- 364
- 11881
- 289
- 80
- 729
- 8836
- 289
- 2209
- 1020
- 144
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