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 36 × 24.
- 2.Use (a − b)² = a² − 2ab + b² to find 27².
- 3.Use (a − b)² = a² − 2ab + b² to find 37².
- 4.Use (a − b)² = a² − 2ab + b² to find 45².
- 5.Use a² − b² = (a + b)(a − b) to find 89² − 13².
- 6.Use (a − b)² = a² − 2ab + b² to find 84².
- 7.If a + b = 10 and ab = 9, what is a² + b²?
- 8.If a − b = 5 and ab = 6, what is a² + b²?
- 9.Use (a + b)² = a² + 2ab + b² to find 12².
- 10.If a − b = 3 and ab = 10, what is a² + b²?
- 11.Find the value of x² + 2xy + y² when x = 8 and y = 7.
- 12.Use (a − b)² = a² − 2ab + b² to find 89².
- 13.Use (a + b)² = a² + 2ab + b² to find 41².
- 14.Use (a + b)(a − b) = a² − b² to find 61 × 59.
- 15.Use (a + b)(a − b) = a² − b² to find 42 × 38.
- 16.Use a² − b² = (a + b)(a − b) to find 91² − 15².
- 17.If a + b = 3 and ab = 2, what is a² + b²?
- 18.Use a² − b² = (a + b)(a − b) to find 36² − 9².
- 19.If a − b = 1 and ab = 6, what is a² + b²?
- 20.Find the value of x² + 2xy + y² when x = 3 and y = 2.
- 21.Use a² − b² = (a + b)(a − b) to find 46² − 40².
- 22.Find the value of x² − y² when x = 5 and y = 2.
- 23.Find the value of x² + 2xy + y² when x = 13 and y = 12.
- 24.Use (a + b)(a − b) = a² − b² to find 41 × 39.
- 25.Use a² − b² = (a + b)(a − b) to find 92² − 91².
- 26.Use (a + b)² = a² + 2ab + b² to find 51².
- 27.Use (a + b)(a − b) = a² − b² to find 45 × 35.
- 28.Use (a + b)² = a² + 2ab + b² to find 42².
- 29.Find the value of x² + 2xy + y² when x = 12 and y = 11.
- 30.Use (a + b)² = a² + 2ab + b² to find 32².
- 31.Use (a + b)(a − b) = a² − b² to find 62 × 58.
- 32.Use (a + b)² = a² + 2ab + b² to find 27².
- 33.Use (a + b)² = a² + 2ab + b² to find 88².
- 34.Use (a − b)² = a² − 2ab + b² to find 92².
- 35.Use (a + b)² = a² + 2ab + b² to find 43².
- 36.Use (a − b)² = a² − 2ab + b² to find 24².
- 37.Use (a − b)² = a² − 2ab + b² to find 32².
- 38.Use (a + b)² = a² + 2ab + b² to find 107².
- 39.Use (a + b)² = a² + 2ab + b² to find 55².
- 40.Find the value of x² − y² when x = 13 and y = 2.
Answer key
- 864
- 729
- 1369
- 2025
- 7752
- 7056
- 82
- 37
- 144
- 29
- 225
- 7921
- 1681
- 3599
- 1596
- 8056
- 5
- 1215
- 13
- 25
- 516
- 21
- 625
- 1599
- 183
- 2601
- 1575
- 1764
- 529
- 1024
- 3596
- 729
- 7744
- 8464
- 1849
- 576
- 1024
- 11449
- 3025
- 165
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