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 − y² when x = 11 and y = 6.
- 2.Use a² − b² = (a + b)(a − b) to find 99² − 86².
- 3.Find the value of x² − 2xy + y² when x = 11 and y = 7.
- 4.Use (a − b)² = a² − 2ab + b² to find 73².
- 5.Find the value of x² − 2xy + y² when x = 3 and y = 2.
- 6.Find the value of x² + 2xy + y² when x = 6 and y = 1.
- 7.If a + b = 14 and ab = 48, what is a² + b²?
- 8.Use (a + b)² = a² + 2ab + b² to find 84².
- 9.Use (a + b)(a − b) = a² − b² to find 32 × 28.
- 10.Use (a − b)² = a² − 2ab + b² to find 86².
- 11.Use (a + b)² = a² + 2ab + b² to find 99².
- 12.Use (a + b)(a − b) = a² − b² to find 94 × 86.
- 13.Use a² − b² = (a + b)(a − b) to find 54² − 1².
- 14.Find the value of x² − y² when x = 5 and y = 1.
- 15.Use a² − b² = (a + b)(a − b) to find 47² − 29².
- 16.Use (a − b)² = a² − 2ab + b² to find 22².
- 17.Use a² − b² = (a + b)(a − b) to find 37² − 27².
- 18.Use a² − b² = (a + b)(a − b) to find 74² − 12².
- 19.Use (a + b)(a − b) = a² − b² to find 109 × 91.
- 20.Use (a + b)(a − b) = a² − b² to find 76 × 64.
- 21.Find the value of x² − 2xy + y² when x = 12 and y = 5.
- 22.Find the value of x² − 2xy + y² when x = 14 and y = 12.
- 23.Use (a + b)² = a² + 2ab + b² to find 106².
- 24.Use (a + b)² = a² + 2ab + b² to find 94².
- 25.Use (a − b)² = a² − 2ab + b² to find 23².
- 26.Use (a − b)² = a² − 2ab + b² to find 42².
- 27.Use (a + b)² = a² + 2ab + b² to find 88².
- 28.Use (a + b)(a − b) = a² − b² to find 36 × 24.
- 29.Use (a + b)² = a² + 2ab + b² to find 19².
- 30.Use (a + b)² = a² + 2ab + b² to find 23².
- 31.Find the value of x² + 2xy + y² when x = 5 and y = 4.
- 32.Use (a − b)² = a² − 2ab + b² to find 85².
- 33.Use (a + b)(a − b) = a² − b² to find 31 × 29.
- 34.Use (a + b)(a − b) = a² − b² to find 62 × 58.
- 35.Find the value of x² − y² when x = 6 and y = 5.
- 36.Find the value of x² − 2xy + y² when x = 8 and y = 5.
- 37.Use (a + b)² = a² + 2ab + b² to find 54².
- 38.Use (a − b)² = a² − 2ab + b² to find 71².
- 39.Use a² − b² = (a + b)(a − b) to find 87² − 36².
- 40.Use (a + b)² = a² + 2ab + b² to find 89².
Answer key
- 85
- 2405
- 16
- 5329
- 1
- 49
- 100
- 7056
- 896
- 7396
- 9801
- 8084
- 2915
- 24
- 1368
- 484
- 640
- 5332
- 9919
- 4864
- 49
- 4
- 11236
- 8836
- 529
- 1764
- 7744
- 864
- 361
- 529
- 81
- 7225
- 899
- 3596
- 11
- 9
- 2916
- 5041
- 6273
- 7921
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