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.
NameDateTime takenScore ___ / 40
- 1.Use (a + b)(a − b) = a² − b² to find 37 × 23.
- 2.Use (a + b)(a − b) = a² − b² to find 46 × 34.
- 3.Use (a − b)² = a² − 2ab + b² to find 41².
- 4.Use (a − b)² = a² − 2ab + b² to find 11².
- 5.Use (a − b)² = a² − 2ab + b² to find 75².
- 6.Use (a + b)² = a² + 2ab + b² to find 39².
- 7.Use (a + b)² = a² + 2ab + b² to find 66².
- 8.Use a² − b² = (a + b)(a − b) to find 77² − 1².
- 9.Use (a + b)² = a² + 2ab + b² to find 103².
- 10.Use (a + b)² = a² + 2ab + b² to find 86².
- 11.Use (a − b)² = a² − 2ab + b² to find 58².
- 12.Find the value of x² − 2xy + y² when x = 8 and y = 2.
- 13.Use (a − b)² = a² − 2ab + b² to find 21².
- 14.Find the value of x² − y² when x = 5 and y = 3.
- 15.Use (a + b)(a − b) = a² − b² to find 31 × 29.
- 16.Use (a + b)(a − b) = a² − b² to find 48 × 32.
- 17.Find the value of x² − y² when x = 9 and y = 6.
- 18.If a − b = 4 and ab = 21, what is a² + b²?
- 19.Use (a + b)² = a² + 2ab + b² to find 91².
- 20.Use (a + b)² = a² + 2ab + b² to find 57².
- 21.Use (a + b)(a − b) = a² − b² to find 67 × 53.
- 22.Use (a − b)² = a² − 2ab + b² to find 18².
- 23.Use (a + b)² = a² + 2ab + b² to find 55².
- 24.Use (a − b)² = a² − 2ab + b² to find 33².
- 25.If a − b = 3 and ab = 70, what is a² + b²?
- 26.Use (a + b)(a − b) = a² − b² to find 83 × 77.
- 27.Use (a − b)² = a² − 2ab + b² to find 47².
- 28.If a + b = 15 and ab = 56, what is a² + b²?
- 29.Use (a + b)(a − b) = a² − b² to find 33 × 27.
- 30.Use (a − b)² = a² − 2ab + b² to find 15².
- 31.Use (a + b)² = a² + 2ab + b² to find 71².
- 32.Find the value of x² − 2xy + y² when x = 12 and y = 5.
- 33.Use (a + b)(a − b) = a² − b² to find 102 × 98.
- 34.Use (a − b)² = a² − 2ab + b² to find 57².
- 35.Use (a + b)² = a² + 2ab + b² to find 104².
- 36.Use (a + b)² = a² + 2ab + b² to find 47².
- 37.Use (a + b)² = a² + 2ab + b² to find 31².
- 38.Find the value of x² − 2xy + y² when x = 8 and y = 1.
- 39.Use a² − b² = (a + b)(a − b) to find 72² − 52².
- 40.Use (a + b)² = a² + 2ab + b² to find 42².
Answer key
- 851
- 1564
- 1681
- 121
- 5625
- 1521
- 4356
- 5928
- 10609
- 7396
- 3364
- 36
- 441
- 16
- 899
- 1536
- 45
- 58
- 8281
- 3249
- 3551
- 324
- 3025
- 1089
- 149
- 6391
- 2209
- 113
- 891
- 225
- 5041
- 49
- 9996
- 3249
- 10816
- 2209
- 961
- 49
- 2480
- 1764
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