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 98².
- 2.Use (a − b)² = a² − 2ab + b² to find 82².
- 3.Use (a − b)² = a² − 2ab + b² to find 52².
- 4.If a + b = 9 and ab = 18, what is a² + b²?
- 5.Use (a + b)² = a² + 2ab + b² to find 77².
- 6.Use a² − b² = (a + b)(a − b) to find 36² − 10².
- 7.Use a² − b² = (a + b)(a − b) to find 48² − 26².
- 8.Find the value of x² + 2xy + y² when x = 15 and y = 11.
- 9.Use (a + b)² = a² + 2ab + b² to find 38².
- 10.If a − b = 7 and ab = 44, what is a² + b²?
- 11.Use (a − b)² = a² − 2ab + b² to find 34².
- 12.Use (a + b)² = a² + 2ab + b² to find 49².
- 13.Use (a + b)² = a² + 2ab + b² to find 37².
- 14.Use (a + b)² = a² + 2ab + b² to find 61².
- 15.Use a² − b² = (a + b)(a − b) to find 41² − 31².
- 16.Use (a + b)(a − b) = a² − b² to find 103 × 97.
- 17.Find the value of x² − y² when x = 6 and y = 5.
- 18.Use (a − b)² = a² − 2ab + b² to find 22².
- 19.Use a² − b² = (a + b)(a − b) to find 48² − 11².
- 20.Find the value of x² + 2xy + y² when x = 6 and y = 1.
- 21.Use (a + b)² = a² + 2ab + b² to find 73².
- 22.Find the value of x² − y² when x = 9 and y = 4.
- 23.Use (a + b)(a − b) = a² − b² to find 35 × 25.
- 24.If a + b = 14 and ab = 24, what is a² + b²?
- 25.Use a² − b² = (a + b)(a − b) to find 79² − 67².
- 26.Use a² − b² = (a + b)(a − b) to find 22² − 12².
- 27.Use (a − b)² = a² − 2ab + b² to find 89².
- 28.Use (a − b)² = a² − 2ab + b² to find 15².
- 29.If a − b = 7 and ab = 8, what is a² + b²?
- 30.If a − b = 4 and ab = 45, what is a² + b²?
- 31.Use a² − b² = (a + b)(a − b) to find 46² − 12².
- 32.Use (a + b)² = a² + 2ab + b² to find 23².
- 33.Use (a + b)² = a² + 2ab + b² to find 69².
- 34.If a − b = 3 and ab = 10, what is a² + b²?
- 35.If a − b = 2 and ab = 80, what is a² + b²?
- 36.Use (a + b)(a − b) = a² − b² to find 42 × 38.
- 37.Use (a + b)² = a² + 2ab + b² to find 52².
- 38.If a − b = 3 and ab = 4, what is a² + b²?
- 39.Find the value of x² − y² when x = 8 and y = 6.
- 40.Use (a + b)² = a² + 2ab + b² to find 39².
Answer key
- 9604
- 6724
- 2704
- 45
- 5929
- 1196
- 1628
- 676
- 1444
- 137
- 1156
- 2401
- 1369
- 3721
- 720
- 9991
- 11
- 484
- 2183
- 49
- 5329
- 65
- 875
- 148
- 1752
- 340
- 7921
- 225
- 65
- 106
- 1972
- 529
- 4761
- 29
- 164
- 1596
- 2704
- 17
- 28
- 1521
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