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 = 1.
- 2.Use (a + b)² = a² + 2ab + b² to find 33².
- 3.Find the value of x² − 2xy + y² when x = 4 and y = 3.
- 4.Use a² − b² = (a + b)(a − b) to find 36² − 31².
- 5.Use (a + b)(a − b) = a² − b² to find 24 × 16.
- 6.Use a² − b² = (a + b)(a − b) to find 89² − 76².
- 7.Use a² − b² = (a + b)(a − b) to find 26² − 20².
- 8.Use a² − b² = (a + b)(a − b) to find 91² − 81².
- 9.Use a² − b² = (a + b)(a − b) to find 80² − 28².
- 10.Use (a + b)² = a² + 2ab + b² to find 78².
- 11.Use a² − b² = (a + b)(a − b) to find 36² − 33².
- 12.If a + b = 8 and ab = 7, what is a² + b²?
- 13.Use a² − b² = (a + b)(a − b) to find 31² − 28².
- 14.Use (a − b)² = a² − 2ab + b² to find 12².
- 15.If a + b = 8 and ab = 12, what is a² + b²?
- 16.Use (a + b)² = a² + 2ab + b² to find 12².
- 17.Find the value of x² − y² when x = 5 and y = 3.
- 18.Find the value of x² − 2xy + y² when x = 14 and y = 9.
- 19.Use (a + b)² = a² + 2ab + b² to find 74².
- 20.Use (a + b)² = a² + 2ab + b² to find 13².
- 21.Use (a − b)² = a² − 2ab + b² to find 33².
- 22.If a − b = 4 and ab = 5, what is a² + b²?
- 23.Use (a − b)² = a² − 2ab + b² to find 54².
- 24.If a + b = 13 and ab = 42, what is a² + b²?
- 25.If a − b = 4 and ab = 12, what is a² + b²?
- 26.If a − b = 2 and ab = 99, what is a² + b²?
- 27.Use a² − b² = (a + b)(a − b) to find 83² − 65².
- 28.If a + b = 15 and ab = 50, what is a² + b²?
- 29.Use a² − b² = (a + b)(a − b) to find 93² − 10².
- 30.Use (a − b)² = a² − 2ab + b² to find 69².
- 31.Find the value of x² + 2xy + y² when x = 10 and y = 8.
- 32.Use (a − b)² = a² − 2ab + b² to find 55².
- 33.Use (a + b)² = a² + 2ab + b² to find 14².
- 34.Use (a + b)² = a² + 2ab + b² to find 79².
- 35.Find the value of x² − 2xy + y² when x = 5 and y = 1.
- 36.Use (a + b)² = a² + 2ab + b² to find 35².
- 37.Find the value of x² − 2xy + y² when x = 9 and y = 6.
- 38.Use a² − b² = (a + b)(a − b) to find 72² − 63².
- 39.Use (a − b)² = a² − 2ab + b² to find 27².
- 40.Use a² − b² = (a + b)(a − b) to find 33² − 8².
Answer key
- 81
- 1089
- 1
- 335
- 384
- 2145
- 276
- 1720
- 5616
- 6084
- 207
- 50
- 177
- 144
- 40
- 144
- 16
- 25
- 5476
- 169
- 1089
- 26
- 2916
- 85
- 40
- 202
- 2664
- 125
- 8549
- 4761
- 324
- 3025
- 196
- 6241
- 16
- 1225
- 9
- 1215
- 729
- 1025
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