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.If a + b = 15 and ab = 56, what is a² + b²?
- 2.Find the value of x² − y² when x = 11 and y = 6.
- 3.Use (a + b)(a − b) = a² − b² to find 91 × 89.
- 4.Find the value of x² + 2xy + y² when x = 5 and y = 1.
- 5.Find the value of x² − y² when x = 12 and y = 3.
- 6.Use (a + b)² = a² + 2ab + b² to find 59².
- 7.Use (a + b)² = a² + 2ab + b² to find 93².
- 8.If a − b = 4 and ab = 5, what is a² + b²?
- 9.Find the value of x² − y² when x = 5 and y = 2.
- 10.Use a² − b² = (a + b)(a − b) to find 61² − 36².
- 11.Use (a − b)² = a² − 2ab + b² to find 12².
- 12.Use (a + b)² = a² + 2ab + b² to find 109².
- 13.Find the value of x² + 2xy + y² when x = 11 and y = 7.
- 14.Use (a + b)² = a² + 2ab + b² to find 99².
- 15.Use (a − b)² = a² − 2ab + b² to find 47².
- 16.Use a² − b² = (a + b)(a − b) to find 49² − 23².
- 17.Use (a + b)(a − b) = a² − b² to find 48 × 32.
- 18.Find the value of x² − 2xy + y² when x = 6 and y = 1.
- 19.Use a² − b² = (a + b)(a − b) to find 37² − 12².
- 20.Find the value of x² + 2xy + y² when x = 7 and y = 3.
- 21.Use (a + b)² = a² + 2ab + b² to find 64².
- 22.If a − b = 1 and ab = 12, what is a² + b²?
- 23.Use a² − b² = (a + b)(a − b) to find 34² − 9².
- 24.Use (a + b)² = a² + 2ab + b² to find 91².
- 25.If a + b = 3 and ab = 2, what is a² + b²?
- 26.If a − b = 3 and ab = 40, what is a² + b²?
- 27.Use (a + b)(a − b) = a² − b² to find 32 × 28.
- 28.Use (a − b)² = a² − 2ab + b² to find 76².
- 29.Use (a + b)² = a² + 2ab + b² to find 58².
- 30.If a − b = 7 and ab = 44, what is a² + b²?
- 31.Use a² − b² = (a + b)(a − b) to find 28² − 25².
- 32.Use a² − b² = (a + b)(a − b) to find 42² − 7².
- 33.Use (a − b)² = a² − 2ab + b² to find 57².
- 34.Use (a − b)² = a² − 2ab + b² to find 11².
- 35.If a + b = 11 and ab = 30, what is a² + b²?
- 36.Use (a + b)(a − b) = a² − b² to find 87 × 73.
- 37.Use a² − b² = (a + b)(a − b) to find 24² − 19².
- 38.Use a² − b² = (a + b)(a − b) to find 58² − 11².
- 39.If a + b = 13 and ab = 40, what is a² + b²?
- 40.Find the value of x² + 2xy + y² when x = 10 and y = 4.
Answer key
- 113
- 85
- 8099
- 36
- 135
- 3481
- 8649
- 26
- 21
- 2425
- 144
- 11881
- 324
- 9801
- 2209
- 1872
- 1536
- 25
- 1225
- 100
- 4096
- 25
- 1075
- 8281
- 5
- 89
- 896
- 5776
- 3364
- 137
- 159
- 1715
- 3249
- 121
- 61
- 6351
- 215
- 3243
- 89
- 196
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