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)(a − b) = a² − b² to find 44 × 36.
- 2.Use (a + b)² = a² + 2ab + b² to find 89².
- 3.Use (a + b)² = a² + 2ab + b² to find 22².
- 4.Find the value of x² − y² when x = 7 and y = 3.
- 5.Use (a + b)² = a² + 2ab + b² to find 109².
- 6.Use a² − b² = (a + b)(a − b) to find 36² − 8².
- 7.Use (a + b)(a − b) = a² − b² to find 92 × 88.
- 8.Use (a + b)(a − b) = a² − b² to find 109 × 91.
- 9.If a − b = 1 and ab = 2, what is a² + b²?
- 10.Use (a + b)(a − b) = a² − b² to find 81 × 79.
- 11.Use a² − b² = (a + b)(a − b) to find 56² − 26².
- 12.Use (a + b)² = a² + 2ab + b² to find 39².
- 13.Use (a + b)(a − b) = a² − b² to find 67 × 53.
- 14.Use (a + b)² = a² + 2ab + b² to find 53².
- 15.Use (a + b)(a − b) = a² − b² to find 43 × 37.
- 16.If a + b = 18 and ab = 80, what is a² + b²?
- 17.Find the value of x² − 2xy + y² when x = 6 and y = 5.
- 18.Use (a − b)² = a² − 2ab + b² to find 34².
- 19.Use (a + b)² = a² + 2ab + b² to find 81².
- 20.Use (a + b)² = a² + 2ab + b² to find 68².
- 21.Use (a − b)² = a² − 2ab + b² to find 24².
- 22.Use (a − b)² = a² − 2ab + b² to find 59².
- 23.Use (a + b)² = a² + 2ab + b² to find 41².
- 24.Find the value of x² − 2xy + y² when x = 11 and y = 5.
- 25.Use (a + b)(a − b) = a² − b² to find 103 × 97.
- 26.Use (a − b)² = a² − 2ab + b² to find 85².
- 27.Use (a + b)(a − b) = a² − b² to find 93 × 87.
- 28.If a − b = 2 and ab = 3, what is a² + b²?
- 29.Use (a + b)² = a² + 2ab + b² to find 99².
- 30.Use (a + b)(a − b) = a² − b² to find 91 × 89.
- 31.Use (a + b)(a − b) = a² − b² to find 77 × 63.
- 32.Find the value of x² + 2xy + y² when x = 13 and y = 11.
- 33.If a + b = 15 and ab = 54, what is a² + b²?
- 34.Find the value of x² − 2xy + y² when x = 15 and y = 3.
- 35.Find the value of x² + 2xy + y² when x = 15 and y = 1.
- 36.Use (a + b)(a − b) = a² − b² to find 41 × 39.
- 37.Use (a + b)(a − b) = a² − b² to find 71 × 69.
- 38.If a + b = 15 and ab = 56, what is a² + b²?
- 39.Use (a − b)² = a² − 2ab + b² to find 94².
- 40.Use (a + b)² = a² + 2ab + b² to find 27².
Answer key
- 1584
- 7921
- 484
- 40
- 11881
- 1232
- 8096
- 9919
- 5
- 6399
- 2460
- 1521
- 3551
- 2809
- 1591
- 164
- 1
- 1156
- 6561
- 4624
- 576
- 3481
- 1681
- 36
- 9991
- 7225
- 8091
- 10
- 9801
- 8099
- 4851
- 576
- 117
- 144
- 256
- 1599
- 4899
- 113
- 8836
- 729
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