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.Find the value of x² + 2xy + y² when x = 11 and y = 1.
- 2.Use a² − b² = (a + b)(a − b) to find 49² − 8².
- 3.If a − b = 2 and ab = 15, what is a² + b²?
- 4.Use a² − b² = (a + b)(a − b) to find 81² − 5².
- 5.Use (a + b)² = a² + 2ab + b² to find 102².
- 6.Use (a + b)(a − b) = a² − b² to find 82 × 78.
- 7.Use (a + b)(a − b) = a² − b² to find 98 × 82.
- 8.Use (a + b)(a − b) = a² − b² to find 25 × 15.
- 9.Use (a − b)² = a² − 2ab + b² to find 13².
- 10.Use a² − b² = (a + b)(a − b) to find 44² − 18².
- 11.Find the value of x² − 2xy + y² when x = 7 and y = 6.
- 12.Use (a + b)² = a² + 2ab + b² to find 57².
- 13.Use (a − b)² = a² − 2ab + b² to find 56².
- 14.Use a² − b² = (a + b)(a − b) to find 31² − 7².
- 15.Use a² − b² = (a + b)(a − b) to find 34² − 20².
- 16.Find the value of x² + 2xy + y² when x = 9 and y = 4.
- 17.Use a² − b² = (a + b)(a − b) to find 29² − 8².
- 18.Use (a + b)(a − b) = a² − b² to find 59 × 41.
- 19.Use (a + b)² = a² + 2ab + b² to find 32².
- 20.Find the value of x² − y² when x = 3 and y = 1.
- 21.If a − b = 9 and ab = 10, what is a² + b²?
- 22.Use a² − b² = (a + b)(a − b) to find 27² − 1².
- 23.Use (a + b)(a − b) = a² − b² to find 97 × 83.
- 24.If a − b = 1 and ab = 12, what is a² + b²?
- 25.Use (a + b)² = a² + 2ab + b² to find 16².
- 26.If a + b = 3 and ab = 2, what is a² + b²?
- 27.Find the value of x² + 2xy + y² when x = 8 and y = 1.
- 28.If a − b = 6 and ab = 7, what is a² + b²?
- 29.Use a² − b² = (a + b)(a − b) to find 66² − 47².
- 30.Use (a − b)² = a² − 2ab + b² to find 34².
- 31.Use (a − b)² = a² − 2ab + b² to find 39².
- 32.Use (a + b)² = a² + 2ab + b² to find 24².
- 33.Use (a + b)² = a² + 2ab + b² to find 77².
- 34.Use (a + b)(a − b) = a² − b² to find 61 × 59.
- 35.Use (a − b)² = a² − 2ab + b² to find 96².
- 36.Use (a + b)(a − b) = a² − b² to find 99 × 81.
- 37.If a + b = 19 and ab = 88, what is a² + b²?
- 38.Use a² − b² = (a + b)(a − b) to find 97² − 7².
- 39.Use (a + b)² = a² + 2ab + b² to find 54².
- 40.Use (a − b)² = a² − 2ab + b² to find 97².
Answer key
- 144
- 2337
- 34
- 6536
- 10404
- 6396
- 8036
- 375
- 169
- 1612
- 1
- 3249
- 3136
- 912
- 756
- 169
- 777
- 2419
- 1024
- 8
- 101
- 728
- 8051
- 25
- 256
- 5
- 81
- 50
- 2147
- 1156
- 1521
- 576
- 5929
- 3599
- 9216
- 8019
- 185
- 9360
- 2916
- 9409
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