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.Find the value of x² − 2xy + y² when x = 8 and y = 7.
- 2.Use (a − b)² = a² − 2ab + b² to find 34².
- 3.If a + b = 10 and ab = 24, what is a² + b²?
- 4.Find the value of x² − y² when x = 5 and y = 3.
- 5.Use (a + b)² = a² + 2ab + b² to find 18².
- 6.Use (a + b)² = a² + 2ab + b² to find 54².
- 7.Use (a + b)² = a² + 2ab + b² to find 46².
- 8.Use a² − b² = (a + b)(a − b) to find 48² − 24².
- 9.Use (a − b)² = a² − 2ab + b² to find 74².
- 10.Find the value of x² − y² when x = 13 and y = 11.
- 11.Use (a + b)(a − b) = a² − b² to find 99 × 81.
- 12.Use a² − b² = (a + b)(a − b) to find 73² − 57².
- 13.Use a² − b² = (a + b)(a − b) to find 94² − 13².
- 14.Use (a + b)(a − b) = a² − b² to find 82 × 78.
- 15.Use (a + b)(a − b) = a² − b² to find 48 × 32.
- 16.Use (a − b)² = a² − 2ab + b² to find 85².
- 17.Use a² − b² = (a + b)(a − b) to find 86² − 26².
- 18.If a + b = 4 and ab = 3, what is a² + b²?
- 19.Use a² − b² = (a + b)(a − b) to find 22² − 15².
- 20.Find the value of x² − y² when x = 5 and y = 1.
- 21.Use (a − b)² = a² − 2ab + b² to find 49².
- 22.Use (a + b)² = a² + 2ab + b² to find 63².
- 23.Use a² − b² = (a + b)(a − b) to find 26² − 14².
- 24.Use (a + b)² = a² + 2ab + b² to find 69².
- 25.Use a² − b² = (a + b)(a − b) to find 30² − 27².
- 26.Use a² − b² = (a + b)(a − b) to find 76² − 15².
- 27.Use (a + b)² = a² + 2ab + b² to find 23².
- 28.Use (a − b)² = a² − 2ab + b² to find 23².
- 29.Use (a + b)² = a² + 2ab + b² to find 88².
- 30.If a + b = 3 and ab = 2, what is a² + b²?
- 31.Use (a − b)² = a² − 2ab + b² to find 28².
- 32.Use a² − b² = (a + b)(a − b) to find 47² − 45².
- 33.Use (a + b)(a − b) = a² − b² to find 51 × 49.
- 34.Use a² − b² = (a + b)(a − b) to find 39² − 5².
- 35.Use (a − b)² = a² − 2ab + b² to find 96².
- 36.Use (a + b)² = a² + 2ab + b² to find 109².
- 37.Use (a + b)(a − b) = a² − b² to find 66 × 54.
- 38.If a − b = 1 and ab = 56, what is a² + b²?
- 39.Use (a − b)² = a² − 2ab + b² to find 13².
- 40.Use a² − b² = (a + b)(a − b) to find 73² − 35².
Answer key
- 1
- 1156
- 52
- 16
- 324
- 2916
- 2116
- 1728
- 5476
- 48
- 8019
- 2080
- 8667
- 6396
- 1536
- 7225
- 6720
- 10
- 259
- 24
- 2401
- 3969
- 480
- 4761
- 171
- 5551
- 529
- 529
- 7744
- 5
- 784
- 184
- 2499
- 1496
- 9216
- 11881
- 3564
- 113
- 169
- 4104
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