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 62².
- 2.Use (a + b)(a − b) = a² − b² to find 64 × 56.
- 3.Use (a + b)² = a² + 2ab + b² to find 22².
- 4.If a − b = 7 and ab = 30, what is a² + b²?
- 5.Use (a − b)² = a² − 2ab + b² to find 12².
- 6.If a + b = 16 and ab = 48, what is a² + b²?
- 7.Use (a + b)² = a² + 2ab + b² to find 91².
- 8.Use a² − b² = (a + b)(a − b) to find 41² − 25².
- 9.Use a² − b² = (a + b)(a − b) to find 79² − 4².
- 10.Find the value of x² − y² when x = 6 and y = 5.
- 11.Use (a + b)(a − b) = a² − b² to find 105 × 95.
- 12.Use a² − b² = (a + b)(a − b) to find 73² − 63².
- 13.Use (a + b)² = a² + 2ab + b² to find 92².
- 14.Use (a − b)² = a² − 2ab + b² to find 61².
- 15.Use (a + b)(a − b) = a² − b² to find 95 × 85.
- 16.Use (a − b)² = a² − 2ab + b² to find 33².
- 17.Use (a − b)² = a² − 2ab + b² to find 53².
- 18.Find the value of x² − y² when x = 15 and y = 13.
- 19.Use (a − b)² = a² − 2ab + b² to find 51².
- 20.If a − b = 1 and ab = 12, what is a² + b²?
- 21.Use (a + b)² = a² + 2ab + b² to find 78².
- 22.If a + b = 3 and ab = 2, what is a² + b²?
- 23.Use (a − b)² = a² − 2ab + b² to find 43².
- 24.If a + b = 10 and ab = 16, what is a² + b²?
- 25.Use a² − b² = (a + b)(a − b) to find 83² − 34².
- 26.Find the value of x² − 2xy + y² when x = 14 and y = 2.
- 27.Use a² − b² = (a + b)(a − b) to find 53² − 22².
- 28.Find the value of x² − y² when x = 10 and y = 1.
- 29.Use a² − b² = (a + b)(a − b) to find 39² − 21².
- 30.If a + b = 5 and ab = 4, what is a² + b²?
- 31.Use (a + b)² = a² + 2ab + b² to find 36².
- 32.Use a² − b² = (a + b)(a − b) to find 65² − 33².
- 33.Use (a − b)² = a² − 2ab + b² to find 73².
- 34.Use (a − b)² = a² − 2ab + b² to find 83².
- 35.If a + b = 13 and ab = 30, what is a² + b²?
- 36.Use (a + b)(a − b) = a² − b² to find 39 × 21.
- 37.Use (a − b)² = a² − 2ab + b² to find 87².
- 38.Use (a − b)² = a² − 2ab + b² to find 39².
- 39.Use (a − b)² = a² − 2ab + b² to find 11².
- 40.Use (a + b)² = a² + 2ab + b² to find 67².
Answer key
- 3844
- 3584
- 484
- 109
- 144
- 160
- 8281
- 1056
- 6225
- 11
- 9975
- 1360
- 8464
- 3721
- 8075
- 1089
- 2809
- 56
- 2601
- 25
- 6084
- 5
- 1849
- 68
- 5733
- 144
- 2325
- 99
- 1080
- 17
- 1296
- 3136
- 5329
- 6889
- 109
- 819
- 7569
- 1521
- 121
- 4489
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