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 69².
- 2.Use (a + b)² = a² + 2ab + b² to find 28².
- 3.Use a² − b² = (a + b)(a − b) to find 70² − 30².
- 4.If a − b = 1 and ab = 30, what is a² + b²?
- 5.Use (a − b)² = a² − 2ab + b² to find 29².
- 6.Use (a − b)² = a² − 2ab + b² to find 16².
- 7.Use (a + b)² = a² + 2ab + b² to find 74².
- 8.Use (a + b)² = a² + 2ab + b² to find 72².
- 9.If a + b = 17 and ab = 72, what is a² + b²?
- 10.If a − b = 4 and ab = 12, what is a² + b²?
- 11.Use (a + b)(a − b) = a² − b² to find 106 × 94.
- 12.Use a² − b² = (a + b)(a − b) to find 78² − 53².
- 13.Find the value of x² − 2xy + y² when x = 4 and y = 1.
- 14.Use a² − b² = (a + b)(a − b) to find 38² − 34².
- 15.Use (a + b)² = a² + 2ab + b² to find 27².
- 16.Use (a + b)(a − b) = a² − b² to find 94 × 86.
- 17.Use (a + b)(a − b) = a² − b² to find 73 × 67.
- 18.Find the value of x² − y² when x = 5 and y = 1.
- 19.Use (a − b)² = a² − 2ab + b² to find 25².
- 20.Find the value of x² − 2xy + y² when x = 11 and y = 1.
- 21.Use (a − b)² = a² − 2ab + b² to find 56².
- 22.Use (a − b)² = a² − 2ab + b² to find 96².
- 23.Find the value of x² + 2xy + y² when x = 8 and y = 5.
- 24.Use (a + b)² = a² + 2ab + b² to find 84².
- 25.If a − b = 7 and ab = 18, what is a² + b²?
- 26.Use (a + b)(a − b) = a² − b² to find 86 × 74.
- 27.Find the value of x² + 2xy + y² when x = 5 and y = 1.
- 28.Find the value of x² − y² when x = 11 and y = 9.
- 29.If a + b = 13 and ab = 40, what is a² + b²?
- 30.Use (a + b)² = a² + 2ab + b² to find 73².
- 31.Use (a − b)² = a² − 2ab + b² to find 82².
- 32.Find the value of x² + 2xy + y² when x = 8 and y = 7.
- 33.Use (a + b)(a − b) = a² − b² to find 36 × 24.
- 34.Use a² − b² = (a + b)(a − b) to find 92² − 72².
- 35.Use (a + b)² = a² + 2ab + b² to find 23².
- 36.Find the value of x² + 2xy + y² when x = 8 and y = 6.
- 37.Use a² − b² = (a + b)(a − b) to find 33² − 20².
- 38.Use (a − b)² = a² − 2ab + b² to find 95².
- 39.Find the value of x² − 2xy + y² when x = 3 and y = 1.
- 40.Use (a + b)² = a² + 2ab + b² to find 32².
Answer key
- 4761
- 784
- 4000
- 61
- 841
- 256
- 5476
- 5184
- 145
- 40
- 9964
- 3275
- 9
- 288
- 729
- 8084
- 4891
- 24
- 625
- 100
- 3136
- 9216
- 169
- 7056
- 85
- 6364
- 36
- 40
- 89
- 5329
- 6724
- 225
- 864
- 3280
- 529
- 196
- 689
- 9025
- 4
- 1024
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