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 = 14 and y = 1.
- 2.Find the value of x² − y² when x = 7 and y = 6.
- 3.Use (a + b)² = a² + 2ab + b² to find 67².
- 4.Use (a + b)(a − b) = a² − b² to find 47 × 33.
- 5.Use a² − b² = (a + b)(a − b) to find 41² − 18².
- 6.Use (a − b)² = a² − 2ab + b² to find 62².
- 7.Use (a + b)(a − b) = a² − b² to find 71 × 69.
- 8.Find the value of x² + 2xy + y² when x = 10 and y = 3.
- 9.Use (a + b)² = a² + 2ab + b² to find 81².
- 10.If a + b = 9 and ab = 14, what is a² + b²?
- 11.Use a² − b² = (a + b)(a − b) to find 43² − 3².
- 12.Use (a − b)² = a² − 2ab + b² to find 68².
- 13.Find the value of x² + 2xy + y² when x = 5 and y = 3.
- 14.Use (a − b)² = a² − 2ab + b² to find 92².
- 15.Use (a + b)² = a² + 2ab + b² to find 76².
- 16.Use (a − b)² = a² − 2ab + b² to find 26².
- 17.If a + b = 15 and ab = 50, what is a² + b²?
- 18.Use a² − b² = (a + b)(a − b) to find 25² − 22².
- 19.Use (a + b)² = a² + 2ab + b² to find 48².
- 20.Use (a + b)(a − b) = a² − b² to find 28 × 12.
- 21.If a + b = 3 and ab = 2, what is a² + b²?
- 22.Use (a + b)² = a² + 2ab + b² to find 21².
- 23.If a − b = 6 and ab = 7, what is a² + b²?
- 24.If a + b = 4 and ab = 3, what is a² + b²?
- 25.Use a² − b² = (a + b)(a − b) to find 90² − 82².
- 26.Use (a + b)² = a² + 2ab + b² to find 98².
- 27.Use a² − b² = (a + b)(a − b) to find 66² − 35².
- 28.Find the value of x² − 2xy + y² when x = 14 and y = 4.
- 29.Use a² − b² = (a + b)(a − b) to find 32² − 1².
- 30.Find the value of x² − 2xy + y² when x = 5 and y = 2.
- 31.Find the value of x² − y² when x = 3 and y = 1.
- 32.If a − b = 2 and ab = 3, what is a² + b²?
- 33.Use a² − b² = (a + b)(a − b) to find 34² − 26².
- 34.Use (a + b)² = a² + 2ab + b² to find 38².
- 35.Use (a + b)² = a² + 2ab + b² to find 87².
- 36.Find the value of x² − y² when x = 4 and y = 2.
- 37.Use (a + b)(a − b) = a² − b² to find 76 × 64.
- 38.Use (a + b)² = a² + 2ab + b² to find 63².
- 39.Use a² − b² = (a + b)(a − b) to find 23² − 1².
- 40.Use (a + b)² = a² + 2ab + b² to find 71².
Answer key
- 169
- 13
- 4489
- 1551
- 1357
- 3844
- 4899
- 169
- 6561
- 53
- 1840
- 4624
- 64
- 8464
- 5776
- 676
- 125
- 141
- 2304
- 336
- 5
- 441
- 50
- 10
- 1376
- 9604
- 3131
- 100
- 1023
- 9
- 8
- 10
- 480
- 1444
- 7569
- 12
- 4864
- 3969
- 528
- 5041
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