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 26².
- 2.Use (a + b)² = a² + 2ab + b² to find 101².
- 3.Find the value of x² − y² when x = 8 and y = 1.
- 4.Use a² − b² = (a + b)(a − b) to find 93² − 8².
- 5.Use (a + b)(a − b) = a² − b² to find 94 × 86.
- 6.Use (a + b)² = a² + 2ab + b² to find 83².
- 7.Use (a + b)(a − b) = a² − b² to find 23 × 17.
- 8.Find the value of x² − y² when x = 13 and y = 3.
- 9.Use (a − b)² = a² − 2ab + b² to find 19².
- 10.Use a² − b² = (a + b)(a − b) to find 64² − 52².
- 11.Use (a + b)² = a² + 2ab + b² to find 13².
- 12.If a − b = 2 and ab = 35, what is a² + b²?
- 13.Find the value of x² − y² when x = 4 and y = 2.
- 14.If a + b = 5 and ab = 6, what is a² + b²?
- 15.Find the value of x² − 2xy + y² when x = 5 and y = 3.
- 16.Use a² − b² = (a + b)(a − b) to find 73² − 22².
- 17.Use a² − b² = (a + b)(a − b) to find 90² − 44².
- 18.Use (a + b)² = a² + 2ab + b² to find 25².
- 19.Use (a + b)(a − b) = a² − b² to find 76 × 64.
- 20.Use (a − b)² = a² − 2ab + b² to find 51².
- 21.Use (a + b)(a − b) = a² − b² to find 56 × 44.
- 22.Find the value of x² − 2xy + y² when x = 5 and y = 4.
- 23.Use (a + b)² = a² + 2ab + b² to find 67².
- 24.Find the value of x² + 2xy + y² when x = 10 and y = 5.
- 25.If a + b = 13 and ab = 40, what is a² + b²?
- 26.Find the value of x² + 2xy + y² when x = 3 and y = 2.
- 27.If a − b = 9 and ab = 10, what is a² + b²?
- 28.Use a² − b² = (a + b)(a − b) to find 71² − 60².
- 29.Use a² − b² = (a + b)(a − b) to find 30² − 24².
- 30.Use a² − b² = (a + b)(a − b) to find 91² − 80².
- 31.Use (a − b)² = a² − 2ab + b² to find 93².
- 32.If a − b = 3 and ab = 28, what is a² + b²?
- 33.Use a² − b² = (a + b)(a − b) to find 36² − 8².
- 34.If a + b = 9 and ab = 14, what is a² + b²?
- 35.Find the value of x² − 2xy + y² when x = 12 and y = 7.
- 36.If a − b = 7 and ab = 30, what is a² + b²?
- 37.Find the value of x² + 2xy + y² when x = 13 and y = 2.
- 38.Use a² − b² = (a + b)(a − b) to find 33² − 17².
- 39.Use (a − b)² = a² − 2ab + b² to find 72².
- 40.Find the value of x² + 2xy + y² when x = 15 and y = 2.
Answer key
- 676
- 10201
- 63
- 8585
- 8084
- 6889
- 391
- 160
- 361
- 1392
- 169
- 74
- 12
- 13
- 4
- 4845
- 6164
- 625
- 4864
- 2601
- 2464
- 1
- 4489
- 225
- 89
- 25
- 101
- 1441
- 324
- 1881
- 8649
- 65
- 1232
- 53
- 25
- 109
- 225
- 800
- 5184
- 289
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