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 a² − b² = (a + b)(a − b) to find 89² − 38².
- 3.Use a² − b² = (a + b)(a − b) to find 84² − 80².
- 4.Use (a + b)² = a² + 2ab + b² to find 77².
- 5.Find the value of x² − 2xy + y² when x = 15 and y = 12.
- 6.Use (a − b)² = a² − 2ab + b² to find 61².
- 7.Find the value of x² + 2xy + y² when x = 7 and y = 2.
- 8.Use a² − b² = (a + b)(a − b) to find 93² − 39².
- 9.Use a² − b² = (a + b)(a − b) to find 41² − 15².
- 10.If a + b = 5 and ab = 4, what is a² + b²?
- 11.Use (a + b)(a − b) = a² − b² to find 32 × 28.
- 12.Find the value of x² − 2xy + y² when x = 12 and y = 7.
- 13.Use (a + b)(a − b) = a² − b² to find 24 × 16.
- 14.Use (a + b)(a − b) = a² − b² to find 53 × 47.
- 15.Find the value of x² − y² when x = 6 and y = 4.
- 16.Use (a + b)² = a² + 2ab + b² to find 16².
- 17.If a + b = 10 and ab = 21, what is a² + b²?
- 18.Use (a − b)² = a² − 2ab + b² to find 53².
- 19.If a + b = 3 and ab = 2, what is a² + b²?
- 20.If a + b = 16 and ab = 48, what is a² + b²?
- 21.If a + b = 13 and ab = 42, what is a² + b²?
- 22.Use (a − b)² = a² − 2ab + b² to find 74².
- 23.Use (a + b)(a − b) = a² − b² to find 46 × 34.
- 24.Find the value of x² − 2xy + y² when x = 5 and y = 1.
- 25.If a + b = 4 and ab = 3, what is a² + b²?
- 26.Use (a + b)(a − b) = a² − b² to find 62 × 58.
- 27.Use a² − b² = (a + b)(a − b) to find 42² − 40².
- 28.Use (a + b)(a − b) = a² − b² to find 77 × 63.
- 29.Use (a + b)² = a² + 2ab + b² to find 67².
- 30.Use a² − b² = (a + b)(a − b) to find 21² − 12².
- 31.Use (a − b)² = a² − 2ab + b² to find 87².
- 32.Find the value of x² + 2xy + y² when x = 13 and y = 3.
- 33.Use a² − b² = (a + b)(a − b) to find 27² − 5².
- 34.Use a² − b² = (a + b)(a − b) to find 99² − 67².
- 35.Use a² − b² = (a + b)(a − b) to find 53² − 26².
- 36.Find the value of x² + 2xy + y² when x = 7 and y = 3.
- 37.Use a² − b² = (a + b)(a − b) to find 22² − 4².
- 38.Use (a − b)² = a² − 2ab + b² to find 49².
- 39.Use (a + b)² = a² + 2ab + b² to find 63².
- 40.Use (a + b)² = a² + 2ab + b² to find 104².
Answer key
- 4624
- 6477
- 656
- 5929
- 9
- 3721
- 81
- 7128
- 1456
- 17
- 896
- 25
- 384
- 2491
- 20
- 256
- 58
- 2809
- 5
- 160
- 85
- 5476
- 1564
- 16
- 10
- 3596
- 164
- 4851
- 4489
- 297
- 7569
- 256
- 704
- 5312
- 2133
- 100
- 468
- 2401
- 3969
- 10816
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