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 68².
- 2.Use (a + b)² = a² + 2ab + b² to find 25².
- 3.If a − b = 1 and ab = 2, what is a² + b²?
- 4.Find the value of x² + 2xy + y² when x = 13 and y = 5.
- 5.Use a² − b² = (a + b)(a − b) to find 77² − 32².
- 6.If a + b = 4 and ab = 3, what is a² + b²?
- 7.Use (a + b)(a − b) = a² − b² to find 28 × 12.
- 8.If a + b = 6 and ab = 5, what is a² + b²?
- 9.Use (a + b)(a − b) = a² − b² to find 58 × 42.
- 10.Use (a − b)² = a² − 2ab + b² to find 89².
- 11.Find the value of x² − 2xy + y² when x = 3 and y = 1.
- 12.Use a² − b² = (a + b)(a − b) to find 95² − 6².
- 13.Use a² − b² = (a + b)(a − b) to find 42² − 11².
- 14.Find the value of x² − 2xy + y² when x = 5 and y = 1.
- 15.Use (a + b)² = a² + 2ab + b² to find 72².
- 16.Use (a − b)² = a² − 2ab + b² to find 48².
- 17.Use a² − b² = (a + b)(a − b) to find 25² − 15².
- 18.Find the value of x² − 2xy + y² when x = 4 and y = 3.
- 19.Use (a + b)² = a² + 2ab + b² to find 33².
- 20.Use (a + b)(a − b) = a² − b² to find 102 × 98.
- 21.If a + b = 6 and ab = 8, what is a² + b²?
- 22.Use (a + b)² = a² + 2ab + b² to find 101².
- 23.Use a² − b² = (a + b)(a − b) to find 39² − 22².
- 24.If a − b = 4 and ab = 12, what is a² + b²?
- 25.Use (a − b)² = a² − 2ab + b² to find 93².
- 26.Use (a + b)² = a² + 2ab + b² to find 29².
- 27.Use a² − b² = (a + b)(a − b) to find 47² − 4².
- 28.If a − b = 3 and ab = 70, what is a² + b²?
- 29.Find the value of x² + 2xy + y² when x = 13 and y = 12.
- 30.Find the value of x² + 2xy + y² when x = 3 and y = 1.
- 31.Use (a + b)(a − b) = a² − b² to find 105 × 95.
- 32.Find the value of x² + 2xy + y² when x = 9 and y = 5.
- 33.If a − b = 7 and ab = 44, what is a² + b²?
- 34.Use (a + b)(a − b) = a² − b² to find 61 × 59.
- 35.Use a² − b² = (a + b)(a − b) to find 20² − 8².
- 36.Use (a − b)² = a² − 2ab + b² to find 95².
- 37.Use (a − b)² = a² − 2ab + b² to find 34².
- 38.Use (a + b)² = a² + 2ab + b² to find 28².
- 39.Use (a + b)(a − b) = a² − b² to find 87 × 73.
- 40.Use (a − b)² = a² − 2ab + b² to find 32².
Answer key
- 4624
- 625
- 5
- 324
- 4905
- 10
- 336
- 26
- 2436
- 7921
- 4
- 8989
- 1643
- 16
- 5184
- 2304
- 400
- 1
- 1089
- 9996
- 20
- 10201
- 1037
- 40
- 8649
- 841
- 2193
- 149
- 625
- 16
- 9975
- 196
- 137
- 3599
- 336
- 9025
- 1156
- 784
- 6351
- 1024
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