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 = 3 and y = 2.
- 2.Find the value of x² + 2xy + y² when x = 5 and y = 1.
- 3.Use (a + b)(a − b) = a² − b² to find 89 × 71.
- 4.Use (a + b)² = a² + 2ab + b² to find 62².
- 5.Use (a + b)(a − b) = a² − b² to find 61 × 59.
- 6.Find the value of x² − y² when x = 3 and y = 2.
- 7.Use (a + b)(a − b) = a² − b² to find 59 × 41.
- 8.Use (a − b)² = a² − 2ab + b² to find 33².
- 9.Use (a + b)² = a² + 2ab + b² to find 54².
- 10.Use (a − b)² = a² − 2ab + b² to find 87².
- 11.Use (a + b)² = a² + 2ab + b² to find 94².
- 12.Find the value of x² + 2xy + y² when x = 7 and y = 5.
- 13.Use (a − b)² = a² − 2ab + b² to find 69².
- 14.Use (a + b)² = a² + 2ab + b² to find 68².
- 15.Use a² − b² = (a + b)(a − b) to find 85² − 7².
- 16.Use (a − b)² = a² − 2ab + b² to find 98².
- 17.Use (a + b)² = a² + 2ab + b² to find 77².
- 18.Find the value of x² + 2xy + y² when x = 8 and y = 4.
- 19.If a + b = 7 and ab = 12, what is a² + b²?
- 20.Use (a + b)² = a² + 2ab + b² to find 96².
- 21.Use (a + b)² = a² + 2ab + b² to find 37².
- 22.Find the value of x² − y² when x = 15 and y = 4.
- 23.Use (a + b)² = a² + 2ab + b² to find 39².
- 24.Find the value of x² + 2xy + y² when x = 15 and y = 13.
- 25.If a + b = 17 and ab = 66, what is a² + b²?
- 26.If a + b = 15 and ab = 56, what is a² + b²?
- 27.Find the value of x² + 2xy + y² when x = 14 and y = 4.
- 28.Find the value of x² − y² when x = 12 and y = 10.
- 29.Find the value of x² + 2xy + y² when x = 14 and y = 2.
- 30.Use (a − b)² = a² − 2ab + b² to find 51².
- 31.Use a² − b² = (a + b)(a − b) to find 39² − 18².
- 32.Use (a − b)² = a² − 2ab + b² to find 42².
- 33.Find the value of x² + 2xy + y² when x = 4 and y = 3.
- 34.If a − b = 2 and ab = 15, what is a² + b²?
- 35.Use (a + b)(a − b) = a² − b² to find 67 × 53.
- 36.Use (a + b)² = a² + 2ab + b² to find 103².
- 37.Find the value of x² − 2xy + y² when x = 13 and y = 6.
- 38.Use (a − b)² = a² − 2ab + b² to find 64².
- 39.Use (a + b)(a − b) = a² − b² to find 38 × 22.
- 40.If a + b = 3 and ab = 2, what is a² + b²?
Answer key
- 25
- 36
- 6319
- 3844
- 3599
- 5
- 2419
- 1089
- 2916
- 7569
- 8836
- 144
- 4761
- 4624
- 7176
- 9604
- 5929
- 144
- 25
- 9216
- 1369
- 209
- 1521
- 784
- 157
- 113
- 324
- 44
- 256
- 2601
- 1197
- 1764
- 49
- 34
- 3551
- 10609
- 49
- 4096
- 836
- 5
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