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 a² − b² = (a + b)(a − b) to find 99² − 67².
- 2.Find the value of x² − 2xy + y² when x = 8 and y = 1.
- 3.Find the value of x² − y² when x = 15 and y = 3.
- 4.Use (a + b)² = a² + 2ab + b² to find 57².
- 5.Use (a + b)² = a² + 2ab + b² to find 49².
- 6.Use (a + b)² = a² + 2ab + b² to find 61².
- 7.Use (a + b)² = a² + 2ab + b² to find 103².
- 8.Use (a + b)² = a² + 2ab + b² to find 65².
- 9.Use a² − b² = (a + b)(a − b) to find 95² − 13².
- 10.Use (a − b)² = a² − 2ab + b² to find 38².
- 11.Use (a − b)² = a² − 2ab + b² to find 16².
- 12.Use a² − b² = (a + b)(a − b) to find 89² − 48².
- 13.Use (a − b)² = a² − 2ab + b² to find 58².
- 14.Find the value of x² − 2xy + y² when x = 11 and y = 1.
- 15.If a + b = 6 and ab = 8, what is a² + b²?
- 16.If a − b = 2 and ab = 3, what is a² + b²?
- 17.Use (a + b)(a − b) = a² − b² to find 43 × 37.
- 18.If a − b = 7 and ab = 8, what is a² + b²?
- 19.Use (a + b)² = a² + 2ab + b² to find 17².
- 20.Use (a + b)² = a² + 2ab + b² to find 82².
- 21.Use (a + b)² = a² + 2ab + b² to find 98².
- 22.Use a² − b² = (a + b)(a − b) to find 61² − 46².
- 23.Use a² − b² = (a + b)(a − b) to find 83² − 79².
- 24.Use (a + b)(a − b) = a² − b² to find 71 × 69.
- 25.Find the value of x² − y² when x = 4 and y = 2.
- 26.Use (a + b)² = a² + 2ab + b² to find 11².
- 27.Use a² − b² = (a + b)(a − b) to find 66² − 33².
- 28.Use (a − b)² = a² − 2ab + b² to find 75².
- 29.Use (a + b)² = a² + 2ab + b² to find 23².
- 30.Use (a + b)² = a² + 2ab + b² to find 79².
- 31.Find the value of x² + 2xy + y² when x = 14 and y = 3.
- 32.Use (a + b)(a − b) = a² − b² to find 25 × 15.
- 33.Use (a + b)² = a² + 2ab + b² to find 34².
- 34.Use (a − b)² = a² − 2ab + b² to find 24².
- 35.Use a² − b² = (a + b)(a − b) to find 77² − 13².
- 36.If a + b = 11 and ab = 18, what is a² + b²?
- 37.Use (a + b)(a − b) = a² − b² to find 32 × 28.
- 38.Find the value of x² − 2xy + y² when x = 15 and y = 11.
- 39.Use (a + b)² = a² + 2ab + b² to find 12².
- 40.If a + b = 19 and ab = 90, what is a² + b²?
Answer key
- 5312
- 49
- 216
- 3249
- 2401
- 3721
- 10609
- 4225
- 8856
- 1444
- 256
- 5617
- 3364
- 100
- 20
- 10
- 1591
- 65
- 289
- 6724
- 9604
- 1605
- 648
- 4899
- 12
- 121
- 3267
- 5625
- 529
- 6241
- 289
- 375
- 1156
- 576
- 5760
- 85
- 896
- 16
- 144
- 181
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