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 77².
- 2.Use (a + b)(a − b) = a² − b² to find 106 × 94.
- 3.Find the value of x² − y² when x = 3 and y = 2.
- 4.Use (a + b)(a − b) = a² − b² to find 31 × 29.
- 5.If a − b = 1 and ab = 6, what is a² + b²?
- 6.Use (a + b)² = a² + 2ab + b² to find 36².
- 7.Use (a + b)² = a² + 2ab + b² to find 104².
- 8.Use (a + b)(a − b) = a² − b² to find 46 × 34.
- 9.Use (a − b)² = a² − 2ab + b² to find 47².
- 10.Use a² − b² = (a + b)(a − b) to find 61² − 30².
- 11.Use (a + b)(a − b) = a² − b² to find 35 × 25.
- 12.Use (a − b)² = a² − 2ab + b² to find 78².
- 13.Find the value of x² + 2xy + y² when x = 3 and y = 1.
- 14.Use (a − b)² = a² − 2ab + b² to find 91².
- 15.Use (a − b)² = a² − 2ab + b² to find 53².
- 16.Use (a + b)(a − b) = a² − b² to find 79 × 61.
- 17.Find the value of x² − 2xy + y² when x = 12 and y = 8.
- 18.Use (a + b)² = a² + 2ab + b² to find 18².
- 19.Find the value of x² + 2xy + y² when x = 5 and y = 4.
- 20.Use (a + b)² = a² + 2ab + b² to find 106².
- 21.Use (a + b)² = a² + 2ab + b² to find 89².
- 22.Use a² − b² = (a + b)(a − b) to find 47² − 28².
- 23.Use (a + b)(a − b) = a² − b² to find 49 × 31.
- 24.Use (a − b)² = a² − 2ab + b² to find 88².
- 25.Use (a + b)² = a² + 2ab + b² to find 57².
- 26.Use (a − b)² = a² − 2ab + b² to find 52².
- 27.Find the value of x² + 2xy + y² when x = 6 and y = 4.
- 28.Use (a + b)² = a² + 2ab + b² to find 42².
- 29.If a − b = 4 and ab = 96, what is a² + b²?
- 30.Use a² − b² = (a + b)(a − b) to find 33² − 26².
- 31.Use (a + b)(a − b) = a² − b² to find 67 × 53.
- 32.Find the value of x² + 2xy + y² when x = 5 and y = 2.
- 33.Use (a − b)² = a² − 2ab + b² to find 37².
- 34.Use (a + b)² = a² + 2ab + b² to find 26².
- 35.If a − b = 2 and ab = 3, what is a² + b²?
- 36.Use (a + b)² = a² + 2ab + b² to find 14².
- 37.Use (a − b)² = a² − 2ab + b² to find 12².
- 38.If a − b = 2 and ab = 35, what is a² + b²?
- 39.If a + b = 13 and ab = 12, what is a² + b²?
- 40.Use a² − b² = (a + b)(a − b) to find 27² − 14².
Answer key
- 5929
- 9964
- 5
- 899
- 13
- 1296
- 10816
- 1564
- 2209
- 2821
- 875
- 6084
- 16
- 8281
- 2809
- 4819
- 16
- 324
- 81
- 11236
- 7921
- 1425
- 1519
- 7744
- 3249
- 2704
- 100
- 1764
- 208
- 413
- 3551
- 49
- 1369
- 676
- 10
- 196
- 144
- 74
- 145
- 533
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