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.
NameDateTime takenScore ___ / 40
- 1.Use (a − b)² = a² − 2ab + b² to find 87².
- 2.Use (a − b)² = a² − 2ab + b² to find 71².
- 3.Find the value of x² − y² when x = 14 and y = 11.
- 4.Find the value of x² − 2xy + y² when x = 6 and y = 1.
- 5.Use (a + b)² = a² + 2ab + b² to find 103².
- 6.Use (a + b)² = a² + 2ab + b² to find 53².
- 7.Use (a + b)(a − b) = a² − b² to find 82 × 78.
- 8.Use (a + b)(a − b) = a² − b² to find 66 × 54.
- 9.Use (a + b)(a − b) = a² − b² to find 35 × 25.
- 10.Use a² − b² = (a + b)(a − b) to find 31² − 23².
- 11.Use (a + b)(a − b) = a² − b² to find 57 × 43.
- 12.Use a² − b² = (a + b)(a − b) to find 42² − 30².
- 13.If a + b = 10 and ab = 16, what is a² + b²?
- 14.Use (a − b)² = a² − 2ab + b² to find 83².
- 15.Use (a + b)(a − b) = a² − b² to find 51 × 49.
- 16.Find the value of x² + 2xy + y² when x = 8 and y = 4.
- 17.Find the value of x² − 2xy + y² when x = 6 and y = 4.
- 18.Use a² − b² = (a + b)(a − b) to find 35² − 34².
- 19.Use a² − b² = (a + b)(a − b) to find 80² − 25².
- 20.Use a² − b² = (a + b)(a − b) to find 74² − 22².
- 21.Find the value of x² − 2xy + y² when x = 3 and y = 2.
- 22.Use a² − b² = (a + b)(a − b) to find 24² − 3².
- 23.Use (a + b)(a − b) = a² − b² to find 101 × 99.
- 24.Find the value of x² + 2xy + y² when x = 4 and y = 3.
- 25.Use (a + b)(a − b) = a² − b² to find 31 × 29.
- 26.Use (a + b)(a − b) = a² − b² to find 41 × 39.
- 27.Use (a + b)(a − b) = a² − b² to find 28 × 12.
- 28.Use (a + b)² = a² + 2ab + b² to find 41².
- 29.Find the value of x² − y² when x = 9 and y = 7.
- 30.Use a² − b² = (a + b)(a − b) to find 40² − 23².
- 31.Use (a + b)² = a² + 2ab + b² to find 64².
- 32.Use (a − b)² = a² − 2ab + b² to find 19².
- 33.Use (a + b)(a − b) = a² − b² to find 65 × 55.
- 34.Use (a − b)² = a² − 2ab + b² to find 95².
- 35.Use a² − b² = (a + b)(a − b) to find 87² − 72².
- 36.If a + b = 11 and ab = 24, what is a² + b²?
- 37.Use (a + b)(a − b) = a² − b² to find 45 × 35.
- 38.Use (a + b)(a − b) = a² − b² to find 85 × 75.
- 39.If a − b = 8 and ab = 33, what is a² + b²?
- 40.Find the value of x² − 2xy + y² when x = 4 and y = 1.
Answer key
- 7569
- 5041
- 75
- 25
- 10609
- 2809
- 6396
- 3564
- 875
- 432
- 2451
- 864
- 68
- 6889
- 2499
- 144
- 4
- 69
- 5775
- 4992
- 1
- 567
- 9999
- 49
- 899
- 1599
- 336
- 1681
- 32
- 1071
- 4096
- 361
- 3575
- 9025
- 2385
- 73
- 1575
- 6375
- 130
- 9
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