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 = 8 and y = 7.
- 2.Use (a − b)² = a² − 2ab + b² to find 24².
- 3.Use (a − b)² = a² − 2ab + b² to find 61².
- 4.Use (a + b)(a − b) = a² − b² to find 22 × 18.
- 5.Find the value of x² + 2xy + y² when x = 13 and y = 7.
- 6.Use a² − b² = (a + b)(a − b) to find 29² − 3².
- 7.Use (a + b)(a − b) = a² − b² to find 39 × 21.
- 8.Use (a + b)² = a² + 2ab + b² to find 74².
- 9.Use a² − b² = (a + b)(a − b) to find 95² − 8².
- 10.Use a² − b² = (a + b)(a − b) to find 63² − 15².
- 11.Use a² − b² = (a + b)(a − b) to find 45² − 37².
- 12.Use (a + b)² = a² + 2ab + b² to find 94².
- 13.If a + b = 12 and ab = 27, what is a² + b²?
- 14.Find the value of x² + 2xy + y² when x = 13 and y = 9.
- 15.Use a² − b² = (a + b)(a − b) to find 64² − 27².
- 16.Use (a + b)² = a² + 2ab + b² to find 33².
- 17.Use a² − b² = (a + b)(a − b) to find 58² − 11².
- 18.If a + b = 10 and ab = 9, what is a² + b²?
- 19.Find the value of x² − 2xy + y² when x = 12 and y = 4.
- 20.If a + b = 11 and ab = 28, what is a² + b²?
- 21.Find the value of x² − 2xy + y² when x = 4 and y = 1.
- 22.Use (a − b)² = a² − 2ab + b² to find 28².
- 23.If a − b = 5 and ab = 24, what is a² + b²?
- 24.Find the value of x² − 2xy + y² when x = 5 and y = 2.
- 25.Find the value of x² − 2xy + y² when x = 11 and y = 3.
- 26.Use a² − b² = (a + b)(a − b) to find 72² − 70².
- 27.If a + b = 18 and ab = 77, what is a² + b²?
- 28.Find the value of x² − y² when x = 6 and y = 5.
- 29.Use (a − b)² = a² − 2ab + b² to find 67².
- 30.Use (a + b)² = a² + 2ab + b² to find 29².
- 31.If a − b = 6 and ab = 40, what is a² + b²?
- 32.Find the value of x² − y² when x = 5 and y = 2.
- 33.Use a² − b² = (a + b)(a − b) to find 31² − 26².
- 34.Use (a + b)² = a² + 2ab + b² to find 51².
- 35.If a − b = 3 and ab = 4, what is a² + b²?
- 36.Use (a + b)(a − b) = a² − b² to find 72 × 68.
- 37.Use (a + b)(a − b) = a² − b² to find 24 × 16.
- 38.Find the value of x² + 2xy + y² when x = 12 and y = 1.
- 39.Use (a + b)² = a² + 2ab + b² to find 25².
- 40.If a + b = 8 and ab = 15, what is a² + b²?
Answer key
- 225
- 576
- 3721
- 396
- 400
- 832
- 819
- 5476
- 8961
- 3744
- 656
- 8836
- 90
- 484
- 3367
- 1089
- 3243
- 82
- 64
- 65
- 9
- 784
- 73
- 9
- 64
- 284
- 170
- 11
- 4489
- 841
- 116
- 21
- 285
- 2601
- 17
- 4896
- 384
- 169
- 625
- 34
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