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 94².
- 2.Use (a + b)(a − b) = a² − b² to find 22 × 18.
- 3.Use (a − b)² = a² − 2ab + b² to find 67².
- 4.Use (a − b)² = a² − 2ab + b² to find 89².
- 5.Find the value of x² + 2xy + y² when x = 8 and y = 3.
- 6.Use a² − b² = (a + b)(a − b) to find 89² − 24².
- 7.Use (a + b)² = a² + 2ab + b² to find 62².
- 8.Use a² − b² = (a + b)(a − b) to find 95² − 75².
- 9.If a + b = 16 and ab = 48, what is a² + b²?
- 10.Use (a − b)² = a² − 2ab + b² to find 35².
- 11.Use a² − b² = (a + b)(a − b) to find 25² − 3².
- 12.If a − b = 2 and ab = 120, what is a² + b²?
- 13.Find the value of x² − 2xy + y² when x = 13 and y = 11.
- 14.Use (a + b)² = a² + 2ab + b² to find 59².
- 15.Use (a − b)² = a² − 2ab + b² to find 56².
- 16.Use (a + b)² = a² + 2ab + b² to find 105².
- 17.If a − b = 6 and ab = 16, what is a² + b²?
- 18.Use (a + b)(a − b) = a² − b² to find 71 × 69.
- 19.Use (a + b)(a − b) = a² − b² to find 68 × 52.
- 20.Use (a − b)² = a² − 2ab + b² to find 97².
- 21.Use (a + b)² = a² + 2ab + b² to find 26².
- 22.If a + b = 9 and ab = 20, what is a² + b²?
- 23.Find the value of x² − y² when x = 3 and y = 1.
- 24.Use (a − b)² = a² − 2ab + b² to find 69².
- 25.Find the value of x² + 2xy + y² when x = 15 and y = 6.
- 26.Use (a + b)(a − b) = a² − b² to find 79 × 61.
- 27.Use a² − b² = (a + b)(a − b) to find 95² − 68².
- 28.Use a² − b² = (a + b)(a − b) to find 23² − 2².
- 29.Use (a − b)² = a² − 2ab + b² to find 47².
- 30.Find the value of x² − 2xy + y² when x = 6 and y = 4.
- 31.Find the value of x² + 2xy + y² when x = 13 and y = 6.
- 32.Use (a + b)(a − b) = a² − b² to find 92 × 88.
- 33.Use (a + b)² = a² + 2ab + b² to find 36².
- 34.Use (a + b)(a − b) = a² − b² to find 59 × 41.
- 35.Use (a − b)² = a² − 2ab + b² to find 49².
- 36.Find the value of x² − y² when x = 13 and y = 4.
- 37.Find the value of x² − y² when x = 10 and y = 1.
- 38.If a + b = 7 and ab = 10, what is a² + b²?
- 39.Use a² − b² = (a + b)(a − b) to find 62² − 15².
- 40.Use a² − b² = (a + b)(a − b) to find 32² − 15².
Answer key
- 8836
- 396
- 4489
- 7921
- 121
- 7345
- 3844
- 3400
- 160
- 1225
- 616
- 244
- 4
- 3481
- 3136
- 11025
- 68
- 4899
- 3536
- 9409
- 676
- 41
- 8
- 4761
- 441
- 4819
- 4401
- 525
- 2209
- 4
- 361
- 8096
- 1296
- 2419
- 2401
- 153
- 99
- 29
- 3619
- 799
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