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 = 12 and y = 5.
- 2.Find the value of x² + 2xy + y² when x = 14 and y = 6.
- 3.Use (a − b)² = a² − 2ab + b² to find 93².
- 4.Use (a + b)² = a² + 2ab + b² to find 105².
- 5.Use (a + b)(a − b) = a² − b² to find 56 × 44.
- 6.Use (a − b)² = a² − 2ab + b² to find 15².
- 7.Find the value of x² − y² when x = 12 and y = 7.
- 8.Use a² − b² = (a + b)(a − b) to find 75² − 34².
- 9.Use (a + b)(a − b) = a² − b² to find 95 × 85.
- 10.Use (a − b)² = a² − 2ab + b² to find 43².
- 11.Use (a − b)² = a² − 2ab + b² to find 53².
- 12.Use a² − b² = (a + b)(a − b) to find 46² − 38².
- 13.If a + b = 7 and ab = 6, what is a² + b²?
- 14.Use (a + b)(a − b) = a² − b² to find 25 × 15.
- 15.Use (a + b)(a − b) = a² − b² to find 102 × 98.
- 16.If a + b = 11 and ab = 18, what is a² + b²?
- 17.Use (a − b)² = a² − 2ab + b² to find 32².
- 18.Use (a − b)² = a² − 2ab + b² to find 14².
- 19.Find the value of x² + 2xy + y² when x = 9 and y = 6.
- 20.Use (a + b)(a − b) = a² − b² to find 38 × 22.
- 21.Find the value of x² − y² when x = 4 and y = 2.
- 22.If a + b = 3 and ab = 2, what is a² + b²?
- 23.Use a² − b² = (a + b)(a − b) to find 87² − 38².
- 24.Use (a − b)² = a² − 2ab + b² to find 16².
- 25.Find the value of x² − 2xy + y² when x = 6 and y = 1.
- 26.Use (a − b)² = a² − 2ab + b² to find 57².
- 27.Find the value of x² + 2xy + y² when x = 14 and y = 2.
- 28.If a + b = 9 and ab = 14, what is a² + b²?
- 29.If a + b = 12 and ab = 11, what is a² + b²?
- 30.Find the value of x² − y² when x = 7 and y = 6.
- 31.Use (a + b)² = a² + 2ab + b² to find 93².
- 32.Use (a + b)² = a² + 2ab + b² to find 99².
- 33.If a − b = 2 and ab = 3, what is a² + b²?
- 34.Use (a + b)² = a² + 2ab + b² to find 68².
- 35.If a + b = 19 and ab = 90, what is a² + b²?
- 36.Use a² − b² = (a + b)(a − b) to find 97² − 35².
- 37.Find the value of x² + 2xy + y² when x = 7 and y = 6.
- 38.Use (a + b)(a − b) = a² − b² to find 49 × 31.
- 39.If a + b = 15 and ab = 54, what is a² + b²?
- 40.Use a² − b² = (a + b)(a − b) to find 98² − 18².
Answer key
- 49
- 400
- 8649
- 11025
- 2464
- 225
- 95
- 4469
- 8075
- 1849
- 2809
- 672
- 37
- 375
- 9996
- 85
- 1024
- 196
- 225
- 836
- 12
- 5
- 6125
- 256
- 25
- 3249
- 256
- 53
- 122
- 13
- 8649
- 9801
- 10
- 4624
- 181
- 8184
- 169
- 1519
- 117
- 9280
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