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 68².
- 2.Use (a − b)² = a² − 2ab + b² to find 82².
- 3.If a − b = 1 and ab = 6, what is a² + b²?
- 4.If a + b = 6 and ab = 8, what is a² + b²?
- 5.Use a² − b² = (a + b)(a − b) to find 79² − 46².
- 6.If a − b = 1 and ab = 2, what is a² + b²?
- 7.Use (a − b)² = a² − 2ab + b² to find 45².
- 8.Use a² − b² = (a + b)(a − b) to find 81² − 17².
- 9.Use (a + b)(a − b) = a² − b² to find 84 × 76.
- 10.Use (a + b)(a − b) = a² − b² to find 104 × 96.
- 11.Find the value of x² + 2xy + y² when x = 14 and y = 5.
- 12.Use (a − b)² = a² − 2ab + b² to find 17².
- 13.Find the value of x² − y² when x = 11 and y = 10.
- 14.Use (a + b)² = a² + 2ab + b² to find 94².
- 15.Use (a − b)² = a² − 2ab + b² to find 94².
- 16.If a + b = 16 and ab = 48, what is a² + b²?
- 17.Use (a − b)² = a² − 2ab + b² to find 58².
- 18.If a + b = 9 and ab = 20, what is a² + b²?
- 19.Find the value of x² + 2xy + y² when x = 11 and y = 9.
- 20.Find the value of x² + 2xy + y² when x = 5 and y = 4.
- 21.If a + b = 12 and ab = 32, what is a² + b²?
- 22.Use (a + b)² = a² + 2ab + b² to find 14².
- 23.Use (a − b)² = a² − 2ab + b² to find 49².
- 24.Use (a + b)² = a² + 2ab + b² to find 102².
- 25.Find the value of x² + 2xy + y² when x = 9 and y = 2.
- 26.Find the value of x² − y² when x = 6 and y = 5.
- 27.Use a² − b² = (a + b)(a − b) to find 23² − 10².
- 28.Use (a + b)(a − b) = a² − b² to find 58 × 42.
- 29.Use (a − b)² = a² − 2ab + b² to find 48².
- 30.Use a² − b² = (a + b)(a − b) to find 34² − 23².
- 31.Use a² − b² = (a + b)(a − b) to find 94² − 56².
- 32.Use a² − b² = (a + b)(a − b) to find 21² − 16².
- 33.Use (a + b)(a − b) = a² − b² to find 36 × 24.
- 34.Use a² − b² = (a + b)(a − b) to find 97² − 71².
- 35.Find the value of x² + 2xy + y² when x = 11 and y = 1.
- 36.Use (a − b)² = a² − 2ab + b² to find 46².
- 37.Use (a − b)² = a² − 2ab + b² to find 26².
- 38.Use (a + b)(a − b) = a² − b² to find 72 × 68.
- 39.Find the value of x² + 2xy + y² when x = 11 and y = 7.
- 40.Find the value of x² + 2xy + y² when x = 10 and y = 7.
Answer key
- 4624
- 6724
- 13
- 20
- 4125
- 5
- 2025
- 6272
- 6384
- 9984
- 361
- 289
- 21
- 8836
- 8836
- 160
- 3364
- 41
- 400
- 81
- 80
- 196
- 2401
- 10404
- 121
- 11
- 429
- 2436
- 2304
- 627
- 5700
- 185
- 864
- 4368
- 144
- 2116
- 676
- 4896
- 324
- 289
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