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.
NameDateTime takenScore ___ / 40
- 1.Use (a − b)² = a² − 2ab + b² to find 15².
- 2.Use (a + b)² = a² + 2ab + b² to find 51².
- 3.Use (a + b)(a − b) = a² − b² to find 48 × 32.
- 4.Use a² − b² = (a + b)(a − b) to find 29² − 24².
- 5.Use a² − b² = (a + b)(a − b) to find 53² − 43².
- 6.Use (a + b)² = a² + 2ab + b² to find 53².
- 7.Use (a + b)² = a² + 2ab + b² to find 86².
- 8.If a + b = 11 and ab = 24, what is a² + b²?
- 9.Use (a + b)(a − b) = a² − b² to find 88 × 72.
- 10.Use (a − b)² = a² − 2ab + b² to find 12².
- 11.Use a² − b² = (a + b)(a − b) to find 26² − 25².
- 12.Use (a − b)² = a² − 2ab + b² to find 13².
- 13.Find the value of x² − 2xy + y² when x = 3 and y = 2.
- 14.Find the value of x² + 2xy + y² when x = 4 and y = 2.
- 15.Use (a + b)(a − b) = a² − b² to find 35 × 25.
- 16.Use (a − b)² = a² − 2ab + b² to find 14².
- 17.Find the value of x² − y² when x = 3 and y = 1.
- 18.Use a² − b² = (a + b)(a − b) to find 71² − 48².
- 19.Use (a − b)² = a² − 2ab + b² to find 39².
- 20.Find the value of x² + 2xy + y² when x = 3 and y = 2.
- 21.Use (a − b)² = a² − 2ab + b² to find 46².
- 22.Use (a − b)² = a² − 2ab + b² to find 99².
- 23.Use (a + b)(a − b) = a² − b² to find 81 × 79.
- 24.Find the value of x² − 2xy + y² when x = 6 and y = 4.
- 25.If a + b = 13 and ab = 22, what is a² + b²?
- 26.Find the value of x² + 2xy + y² when x = 14 and y = 1.
- 27.Use a² − b² = (a + b)(a − b) to find 96² − 73².
- 28.If a − b = 3 and ab = 10, what is a² + b²?
- 29.Find the value of x² + 2xy + y² when x = 4 and y = 3.
- 30.Use (a + b)² = a² + 2ab + b² to find 76².
- 31.Find the value of x² − 2xy + y² when x = 12 and y = 1.
- 32.Use (a − b)² = a² − 2ab + b² to find 35².
- 33.Use (a + b)² = a² + 2ab + b² to find 32².
- 34.Find the value of x² − 2xy + y² when x = 3 and y = 1.
- 35.Use (a − b)² = a² − 2ab + b² to find 49².
- 36.Use (a + b)² = a² + 2ab + b² to find 109².
- 37.Use (a − b)² = a² − 2ab + b² to find 69².
- 38.Find the value of x² − 2xy + y² when x = 11 and y = 7.
- 39.Find the value of x² + 2xy + y² when x = 15 and y = 11.
- 40.Use (a + b)(a − b) = a² − b² to find 79 × 61.
Answer key
- 225
- 2601
- 1536
- 265
- 960
- 2809
- 7396
- 73
- 6336
- 144
- 51
- 169
- 1
- 36
- 875
- 196
- 8
- 2737
- 1521
- 25
- 2116
- 9801
- 6399
- 4
- 125
- 225
- 3887
- 29
- 49
- 5776
- 121
- 1225
- 1024
- 4
- 2401
- 11881
- 4761
- 16
- 676
- 4819
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