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 92².
- 2.Use a² − b² = (a + b)(a − b) to find 27² − 4².
- 3.If a + b = 14 and ab = 40, what is a² + b²?
- 4.Use (a − b)² = a² − 2ab + b² to find 12².
- 5.Use (a − b)² = a² − 2ab + b² to find 44².
- 6.Use (a + b)² = a² + 2ab + b² to find 15².
- 7.Use (a + b)(a − b) = a² − b² to find 47 × 33.
- 8.Use (a + b)² = a² + 2ab + b² to find 55².
- 9.Use (a + b)² = a² + 2ab + b² to find 82².
- 10.Use (a − b)² = a² − 2ab + b² to find 48².
- 11.Use (a − b)² = a² − 2ab + b² to find 87².
- 12.If a + b = 6 and ab = 5, what is a² + b²?
- 13.Find the value of x² + 2xy + y² when x = 4 and y = 3.
- 14.Use (a − b)² = a² − 2ab + b² to find 73².
- 15.Use (a − b)² = a² − 2ab + b² to find 15².
- 16.Use (a + b)² = a² + 2ab + b² to find 36².
- 17.Find the value of x² − y² when x = 6 and y = 5.
- 18.Find the value of x² + 2xy + y² when x = 14 and y = 2.
- 19.Use (a + b)(a − b) = a² − b² to find 67 × 53.
- 20.Use a² − b² = (a + b)(a − b) to find 63² − 11².
- 21.If a + b = 14 and ab = 24, what is a² + b²?
- 22.Use (a + b)(a − b) = a² − b² to find 99 × 81.
- 23.Use a² − b² = (a + b)(a − b) to find 39² − 7².
- 24.Use a² − b² = (a + b)(a − b) to find 83² − 72².
- 25.Use (a − b)² = a² − 2ab + b² to find 78².
- 26.Use a² − b² = (a + b)(a − b) to find 29² − 23².
- 27.Find the value of x² + 2xy + y² when x = 7 and y = 2.
- 28.Use a² − b² = (a + b)(a − b) to find 31² − 10².
- 29.Use (a + b)² = a² + 2ab + b² to find 96².
- 30.Use (a + b)² = a² + 2ab + b² to find 56².
- 31.Use a² − b² = (a + b)(a − b) to find 54² − 35².
- 32.Find the value of x² − y² when x = 4 and y = 2.
- 33.Use (a − b)² = a² − 2ab + b² to find 47².
- 34.Use (a + b)² = a² + 2ab + b² to find 76².
- 35.Use (a + b)² = a² + 2ab + b² to find 46².
- 36.Use (a − b)² = a² − 2ab + b² to find 24².
- 37.If a + b = 16 and ab = 60, what is a² + b²?
- 38.Use (a − b)² = a² − 2ab + b² to find 19².
- 39.If a + b = 11 and ab = 30, what is a² + b²?
- 40.Find the value of x² + 2xy + y² when x = 10 and y = 4.
Answer key
- 8464
- 713
- 116
- 144
- 1936
- 225
- 1551
- 3025
- 6724
- 2304
- 7569
- 26
- 49
- 5329
- 225
- 1296
- 11
- 256
- 3551
- 3848
- 148
- 8019
- 1472
- 1705
- 6084
- 312
- 81
- 861
- 9216
- 3136
- 1691
- 12
- 2209
- 5776
- 2116
- 576
- 136
- 361
- 61
- 196
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