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 85² − 4².
- 2.Use (a + b)(a − b) = a² − b² to find 94 × 86.
- 3.Use (a + b)(a − b) = a² − b² to find 75 × 65.
- 4.Use (a + b)² = a² + 2ab + b² to find 23².
- 5.Use (a − b)² = a² − 2ab + b² to find 44².
- 6.Use (a + b)² = a² + 2ab + b² to find 44².
- 7.Use (a + b)² = a² + 2ab + b² to find 88².
- 8.Use a² − b² = (a + b)(a − b) to find 98² − 32².
- 9.Use (a + b)² = a² + 2ab + b² to find 17².
- 10.Use a² − b² = (a + b)(a − b) to find 60² − 44².
- 11.Use (a + b)(a − b) = a² − b² to find 23 × 17.
- 12.If a − b = 10 and ab = 11, what is a² + b²?
- 13.Use a² − b² = (a + b)(a − b) to find 86² − 39².
- 14.Find the value of x² − 2xy + y² when x = 5 and y = 1.
- 15.Use (a + b)(a − b) = a² − b² to find 73 × 67.
- 16.Find the value of x² + 2xy + y² when x = 3 and y = 1.
- 17.Find the value of x² + 2xy + y² when x = 7 and y = 1.
- 18.Use (a + b)² = a² + 2ab + b² to find 12².
- 19.Use a² − b² = (a + b)(a − b) to find 23² − 6².
- 20.If a + b = 5 and ab = 4, what is a² + b²?
- 21.Find the value of x² − y² when x = 14 and y = 6.
- 22.Use (a + b)² = a² + 2ab + b² to find 52².
- 23.Find the value of x² − 2xy + y² when x = 12 and y = 4.
- 24.Find the value of x² − 2xy + y² when x = 10 and y = 6.
- 25.Use (a − b)² = a² − 2ab + b² to find 24².
- 26.Find the value of x² − 2xy + y² when x = 14 and y = 13.
- 27.Find the value of x² − 2xy + y² when x = 6 and y = 4.
- 28.Find the value of x² − 2xy + y² when x = 3 and y = 2.
- 29.If a − b = 2 and ab = 8, what is a² + b²?
- 30.Find the value of x² − y² when x = 6 and y = 4.
- 31.Use (a + b)(a − b) = a² − b² to find 58 × 42.
- 32.If a + b = 3 and ab = 2, what is a² + b²?
- 33.Use (a + b)(a − b) = a² − b² to find 77 × 63.
- 34.Find the value of x² − y² when x = 3 and y = 1.
- 35.Use (a − b)² = a² − 2ab + b² to find 38².
- 36.Use (a − b)² = a² − 2ab + b² to find 13².
- 37.Use (a + b)² = a² + 2ab + b² to find 69².
- 38.Use (a − b)² = a² − 2ab + b² to find 65².
- 39.If a − b = 2 and ab = 3, what is a² + b²?
- 40.Use a² − b² = (a + b)(a − b) to find 99² − 45².
Answer key
- 7209
- 8084
- 4875
- 529
- 1936
- 1936
- 7744
- 8580
- 289
- 1664
- 391
- 122
- 5875
- 16
- 4891
- 16
- 64
- 144
- 493
- 17
- 160
- 2704
- 64
- 16
- 576
- 1
- 4
- 1
- 20
- 20
- 2436
- 5
- 4851
- 8
- 1444
- 169
- 4761
- 4225
- 10
- 7776
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