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 − y² when x = 9 and y = 6.
- 2.Use (a − b)² = a² − 2ab + b² to find 19².
- 3.Find the value of x² − 2xy + y² when x = 10 and y = 4.
- 4.Use (a + b)(a − b) = a² − b² to find 87 × 73.
- 5.Use (a + b)² = a² + 2ab + b² to find 97².
- 6.Use (a + b)² = a² + 2ab + b² to find 33².
- 7.Use a² − b² = (a + b)(a − b) to find 84² − 54².
- 8.Use (a + b)² = a² + 2ab + b² to find 16².
- 9.Use (a + b)(a − b) = a² − b² to find 71 × 69.
- 10.Use (a + b)² = a² + 2ab + b² to find 37².
- 11.Use (a + b)² = a² + 2ab + b² to find 21².
- 12.Use (a + b)(a − b) = a² − b² to find 66 × 54.
- 13.Use (a − b)² = a² − 2ab + b² to find 59².
- 14.If a + b = 8 and ab = 15, what is a² + b²?
- 15.Use (a − b)² = a² − 2ab + b² to find 58².
- 16.Use (a − b)² = a² − 2ab + b² to find 69².
- 17.Use (a − b)² = a² − 2ab + b² to find 98².
- 18.Use (a + b)² = a² + 2ab + b² to find 105².
- 19.Use (a + b)(a − b) = a² − b² to find 88 × 72.
- 20.If a − b = 2 and ab = 3, what is a² + b²?
- 21.Find the value of x² − y² when x = 5 and y = 4.
- 22.Use (a + b)(a − b) = a² − b² to find 43 × 37.
- 23.Use (a − b)² = a² − 2ab + b² to find 81².
- 24.Use (a + b)(a − b) = a² − b² to find 108 × 92.
- 25.Use a² − b² = (a + b)(a − b) to find 89² − 44².
- 26.Find the value of x² − y² when x = 10 and y = 3.
- 27.If a − b = 6 and ab = 7, what is a² + b²?
- 28.Find the value of x² + 2xy + y² when x = 11 and y = 3.
- 29.Find the value of x² + 2xy + y² when x = 5 and y = 4.
- 30.Use (a + b)(a − b) = a² − b² to find 69 × 51.
- 31.Use (a + b)(a − b) = a² − b² to find 61 × 59.
- 32.Use (a + b)² = a² + 2ab + b² to find 46².
- 33.Use (a + b)(a − b) = a² − b² to find 82 × 78.
- 34.Use (a + b)(a − b) = a² − b² to find 109 × 91.
- 35.Use (a + b)² = a² + 2ab + b² to find 32².
- 36.If a − b = 4 and ab = 32, what is a² + b²?
- 37.Use (a + b)² = a² + 2ab + b² to find 69².
- 38.Use (a + b)² = a² + 2ab + b² to find 43².
- 39.Use a² − b² = (a + b)(a − b) to find 43² − 29².
- 40.Use (a − b)² = a² − 2ab + b² to find 13².
Answer key
- 45
- 361
- 36
- 6351
- 9409
- 1089
- 4140
- 256
- 4899
- 1369
- 441
- 3564
- 3481
- 34
- 3364
- 4761
- 9604
- 11025
- 6336
- 10
- 9
- 1591
- 6561
- 9936
- 5985
- 91
- 50
- 196
- 81
- 3519
- 3599
- 2116
- 6396
- 9919
- 1024
- 80
- 4761
- 1849
- 1008
- 169
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