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)(a − b) = a² − b² to find 79 × 61.
- 2.Use (a + b)(a − b) = a² − b² to find 73 × 67.
- 3.Use (a + b)(a − b) = a² − b² to find 81 × 79.
- 4.Use a² − b² = (a + b)(a − b) to find 44² − 14².
- 5.Use (a − b)² = a² − 2ab + b² to find 98².
- 6.Find the value of x² − y² when x = 6 and y = 4.
- 7.If a − b = 3 and ab = 4, what is a² + b²?
- 8.Find the value of x² + 2xy + y² when x = 5 and y = 3.
- 9.Find the value of x² − 2xy + y² when x = 5 and y = 3.
- 10.Use a² − b² = (a + b)(a − b) to find 94² − 27².
- 11.Find the value of x² − y² when x = 4 and y = 2.
- 12.If a + b = 8 and ab = 7, what is a² + b²?
- 13.Find the value of x² − y² when x = 6 and y = 5.
- 14.Find the value of x² − 2xy + y² when x = 14 and y = 6.
- 15.Use (a − b)² = a² − 2ab + b² to find 19².
- 16.Use (a + b)² = a² + 2ab + b² to find 41².
- 17.Use (a + b)² = a² + 2ab + b² to find 65².
- 18.Use (a + b)² = a² + 2ab + b² to find 15².
- 19.Find the value of x² − y² when x = 5 and y = 4.
- 20.If a + b = 7 and ab = 10, what is a² + b²?
- 21.Use (a + b)(a − b) = a² − b² to find 82 × 78.
- 22.Use (a + b)² = a² + 2ab + b² to find 44².
- 23.Use a² − b² = (a + b)(a − b) to find 41² − 1².
- 24.Use (a + b)² = a² + 2ab + b² to find 79².
- 25.Find the value of x² + 2xy + y² when x = 14 and y = 4.
- 26.Use a² − b² = (a + b)(a − b) to find 32² − 26².
- 27.Find the value of x² − 2xy + y² when x = 3 and y = 1.
- 28.If a − b = 2 and ab = 3, what is a² + b²?
- 29.Find the value of x² + 2xy + y² when x = 12 and y = 11.
- 30.Use (a + b)(a − b) = a² − b² to find 106 × 94.
- 31.Use (a − b)² = a² − 2ab + b² to find 46².
- 32.Find the value of x² + 2xy + y² when x = 15 and y = 9.
- 33.Find the value of x² − y² when x = 7 and y = 3.
- 34.If a − b = 4 and ab = 5, what is a² + b²?
- 35.Find the value of x² + 2xy + y² when x = 10 and y = 6.
- 36.Use (a − b)² = a² − 2ab + b² to find 52².
- 37.Find the value of x² + 2xy + y² when x = 3 and y = 1.
- 38.Use a² − b² = (a + b)(a − b) to find 72² − 37².
- 39.Use (a + b)(a − b) = a² − b² to find 62 × 58.
- 40.Find the value of x² + 2xy + y² when x = 13 and y = 7.
Answer key
- 4819
- 4891
- 6399
- 1740
- 9604
- 20
- 17
- 64
- 4
- 8107
- 12
- 50
- 11
- 64
- 361
- 1681
- 4225
- 225
- 9
- 29
- 6396
- 1936
- 1680
- 6241
- 324
- 348
- 4
- 10
- 529
- 9964
- 2116
- 576
- 40
- 26
- 256
- 2704
- 16
- 3815
- 3596
- 400
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