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 a² − b² = (a + b)(a − b) to find 48² − 16².
- 2.Use (a − b)² = a² − 2ab + b² to find 91².
- 3.If a + b = 5 and ab = 6, what is a² + b²?
- 4.Use (a + b)² = a² + 2ab + b² to find 93².
- 5.Use (a − b)² = a² − 2ab + b² to find 18².
- 6.Use (a + b)² = a² + 2ab + b² to find 98².
- 7.Use a² − b² = (a + b)(a − b) to find 84² − 36².
- 8.Use (a − b)² = a² − 2ab + b² to find 48².
- 9.Find the value of x² + 2xy + y² when x = 7 and y = 4.
- 10.Use (a + b)² = a² + 2ab + b² to find 87².
- 11.Use (a + b)(a − b) = a² − b² to find 31 × 29.
- 12.Find the value of x² − y² when x = 5 and y = 1.
- 13.Use (a + b)(a − b) = a² − b² to find 77 × 63.
- 14.Use a² − b² = (a + b)(a − b) to find 79² − 73².
- 15.If a − b = 2 and ab = 35, what is a² + b²?
- 16.Find the value of x² + 2xy + y² when x = 5 and y = 3.
- 17.Use a² − b² = (a + b)(a − b) to find 85² − 70².
- 18.Use a² − b² = (a + b)(a − b) to find 44² − 31².
- 19.Use (a − b)² = a² − 2ab + b² to find 26².
- 20.Use (a + b)(a − b) = a² − b² to find 108 × 92.
- 21.Find the value of x² + 2xy + y² when x = 13 and y = 12.
- 22.Find the value of x² − 2xy + y² when x = 12 and y = 8.
- 23.Use (a − b)² = a² − 2ab + b² to find 88².
- 24.Use (a + b)² = a² + 2ab + b² to find 61².
- 25.Use (a + b)(a − b) = a² − b² to find 95 × 85.
- 26.Use (a − b)² = a² − 2ab + b² to find 29².
- 27.Find the value of x² − 2xy + y² when x = 13 and y = 4.
- 28.Use (a + b)² = a² + 2ab + b² to find 67².
- 29.Find the value of x² − y² when x = 9 and y = 2.
- 30.Find the value of x² − y² when x = 3 and y = 2.
- 31.Use (a + b)² = a² + 2ab + b² to find 103².
- 32.Use (a + b)² = a² + 2ab + b² to find 74².
- 33.Find the value of x² − y² when x = 12 and y = 10.
- 34.If a − b = 1 and ab = 2, what is a² + b²?
- 35.Use (a − b)² = a² − 2ab + b² to find 76².
- 36.If a − b = 7 and ab = 44, what is a² + b²?
- 37.Find the value of x² + 2xy + y² when x = 12 and y = 9.
- 38.If a + b = 3 and ab = 2, what is a² + b²?
- 39.Use a² − b² = (a + b)(a − b) to find 26² − 13².
- 40.Use (a + b)² = a² + 2ab + b² to find 53².
Answer key
- 2048
- 8281
- 13
- 8649
- 324
- 9604
- 5760
- 2304
- 121
- 7569
- 899
- 24
- 4851
- 912
- 74
- 64
- 2325
- 975
- 676
- 9936
- 625
- 16
- 7744
- 3721
- 8075
- 841
- 81
- 4489
- 77
- 5
- 10609
- 5476
- 44
- 5
- 5776
- 137
- 441
- 5
- 507
- 2809
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