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)² = a² − 2ab + b² to find 68².
- 2.Use (a − b)² = a² − 2ab + b² to find 82².
- 3.Find the value of x² + 2xy + y² when x = 12 and y = 6.
- 4.Use (a + b)(a − b) = a² − b² to find 99 × 81.
- 5.Use (a + b)(a − b) = a² − b² to find 74 × 66.
- 6.Use (a − b)² = a² − 2ab + b² to find 48².
- 7.Find the value of x² − 2xy + y² when x = 14 and y = 11.
- 8.If a + b = 6 and ab = 8, what is a² + b²?
- 9.Use (a + b)² = a² + 2ab + b² to find 89².
- 10.Use (a + b)(a − b) = a² − b² to find 77 × 63.
- 11.Find the value of x² − y² when x = 15 and y = 11.
- 12.Use a² − b² = (a + b)(a − b) to find 37² − 14².
- 13.Use (a − b)² = a² − 2ab + b² to find 16².
- 14.Use a² − b² = (a + b)(a − b) to find 91² − 18².
- 15.Use (a + b)² = a² + 2ab + b² to find 36².
- 16.Use (a − b)² = a² − 2ab + b² to find 15².
- 17.If a − b = 1 and ab = 2, what is a² + b²?
- 18.Use (a + b)(a − b) = a² − b² to find 72 × 68.
- 19.Use (a − b)² = a² − 2ab + b² to find 58².
- 20.Use a² − b² = (a + b)(a − b) to find 95² − 78².
- 21.Use (a + b)(a − b) = a² − b² to find 95 × 85.
- 22.Use a² − b² = (a + b)(a − b) to find 34² − 27².
- 23.Use (a + b)² = a² + 2ab + b² to find 76².
- 24.Use a² − b² = (a + b)(a − b) to find 27² − 13².
- 25.Find the value of x² − 2xy + y² when x = 13 and y = 6.
- 26.If a + b = 16 and ab = 60, what is a² + b²?
- 27.Use (a + b)(a − b) = a² − b² to find 83 × 77.
- 28.Use (a + b)² = a² + 2ab + b² to find 22².
- 29.Use a² − b² = (a + b)(a − b) to find 74² − 7².
- 30.Use a² − b² = (a + b)(a − b) to find 62² − 26².
- 31.Use (a − b)² = a² − 2ab + b² to find 47².
- 32.If a − b = 5 and ab = 6, what is a² + b²?
- 33.Use (a + b)(a − b) = a² − b² to find 101 × 99.
- 34.If a − b = 2 and ab = 3, what is a² + b²?
- 35.Find the value of x² − y² when x = 12 and y = 8.
- 36.Use a² − b² = (a + b)(a − b) to find 52² − 37².
- 37.Find the value of x² + 2xy + y² when x = 15 and y = 4.
- 38.Use a² − b² = (a + b)(a − b) to find 62² − 30².
- 39.Use (a + b)² = a² + 2ab + b² to find 53².
- 40.Use (a + b)(a − b) = a² − b² to find 73 × 67.
Answer key
- 4624
- 6724
- 324
- 8019
- 4884
- 2304
- 9
- 20
- 7921
- 4851
- 104
- 1173
- 256
- 7957
- 1296
- 225
- 5
- 4896
- 3364
- 2941
- 8075
- 427
- 5776
- 560
- 49
- 136
- 6391
- 484
- 5427
- 3168
- 2209
- 37
- 9999
- 10
- 80
- 1335
- 361
- 2944
- 2809
- 4891
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