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 64².
- 2.Find the value of x² + 2xy + y² when x = 13 and y = 9.
- 3.If a + b = 8 and ab = 15, what is a² + b²?
- 4.Use (a + b)² = a² + 2ab + b² to find 101².
- 5.If a + b = 22 and ab = 120, what is a² + b²?
- 6.Use (a + b)(a − b) = a² − b² to find 59 × 41.
- 7.Use (a + b)(a − b) = a² − b² to find 53 × 47.
- 8.Find the value of x² + 2xy + y² when x = 4 and y = 3.
- 9.Find the value of x² + 2xy + y² when x = 5 and y = 1.
- 10.Use (a + b)(a − b) = a² − b² to find 64 × 56.
- 11.Use (a − b)² = a² − 2ab + b² to find 88².
- 12.Use (a + b)(a − b) = a² − b² to find 29 × 11.
- 13.If a + b = 5 and ab = 6, what is a² + b²?
- 14.Find the value of x² − y² when x = 10 and y = 8.
- 15.Use (a − b)² = a² − 2ab + b² to find 11².
- 16.Use (a − b)² = a² − 2ab + b² to find 62².
- 17.Find the value of x² + 2xy + y² when x = 6 and y = 5.
- 18.Use (a + b)² = a² + 2ab + b² to find 63².
- 19.If a − b = 1 and ab = 2, what is a² + b²?
- 20.Find the value of x² + 2xy + y² when x = 6 and y = 4.
- 21.Use (a − b)² = a² − 2ab + b² to find 82².
- 22.Use (a + b)(a − b) = a² − b² to find 51 × 49.
- 23.Find the value of x² − 2xy + y² when x = 12 and y = 10.
- 24.Use (a + b)(a − b) = a² − b² to find 101 × 99.
- 25.Use (a + b)² = a² + 2ab + b² to find 27².
- 26.Use (a + b)(a − b) = a² − b² to find 105 × 95.
- 27.Use (a + b)² = a² + 2ab + b² to find 36².
- 28.If a + b = 7 and ab = 12, what is a² + b²?
- 29.Use (a + b)² = a² + 2ab + b² to find 51².
- 30.Use (a + b)(a − b) = a² − b² to find 41 × 39.
- 31.Find the value of x² − 2xy + y² when x = 14 and y = 1.
- 32.Use (a − b)² = a² − 2ab + b² to find 73².
- 33.Use (a − b)² = a² − 2ab + b² to find 39².
- 34.Use (a − b)² = a² − 2ab + b² to find 94².
- 35.Find the value of x² + 2xy + y² when x = 3 and y = 1.
- 36.Use (a − b)² = a² − 2ab + b² to find 13².
- 37.Use a² − b² = (a + b)(a − b) to find 68² − 6².
- 38.Find the value of x² + 2xy + y² when x = 5 and y = 2.
- 39.Use (a − b)² = a² − 2ab + b² to find 53².
- 40.Use (a + b)(a − b) = a² − b² to find 32 × 28.
Answer key
- 4096
- 484
- 34
- 10201
- 244
- 2419
- 2491
- 49
- 36
- 3584
- 7744
- 319
- 13
- 36
- 121
- 3844
- 121
- 3969
- 5
- 100
- 6724
- 2499
- 4
- 9999
- 729
- 9975
- 1296
- 25
- 2601
- 1599
- 169
- 5329
- 1521
- 8836
- 16
- 169
- 4588
- 49
- 2809
- 896
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