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 71².
- 2.Use (a − b)² = a² − 2ab + b² to find 94².
- 3.Use a² − b² = (a + b)(a − b) to find 89² − 19².
- 4.Find the value of x² + 2xy + y² when x = 8 and y = 1.
- 5.Use (a + b)(a − b) = a² − b² to find 42 × 38.
- 6.Use (a + b)² = a² + 2ab + b² to find 35².
- 7.If a + b = 20 and ab = 99, what is a² + b²?
- 8.Use a² − b² = (a + b)(a − b) to find 84² − 3².
- 9.Find the value of x² − y² when x = 7 and y = 4.
- 10.Use (a − b)² = a² − 2ab + b² to find 32².
- 11.If a − b = 3 and ab = 88, what is a² + b²?
- 12.If a + b = 11 and ab = 18, what is a² + b²?
- 13.Use (a + b)² = a² + 2ab + b² to find 39².
- 14.Use (a + b)² = a² + 2ab + b² to find 81².
- 15.Use (a + b)² = a² + 2ab + b² to find 41².
- 16.Find the value of x² − y² when x = 12 and y = 1.
- 17.If a + b = 3 and ab = 2, what is a² + b²?
- 18.Use (a + b)(a − b) = a² − b² to find 76 × 64.
- 19.If a − b = 3 and ab = 28, what is a² + b²?
- 20.Use (a + b)² = a² + 2ab + b² to find 63².
- 21.Use (a − b)² = a² − 2ab + b² to find 47².
- 22.If a − b = 8 and ab = 33, what is a² + b²?
- 23.Use (a + b)(a − b) = a² − b² to find 66 × 54.
- 24.Use a² − b² = (a + b)(a − b) to find 25² − 18².
- 25.Use a² − b² = (a + b)(a − b) to find 38² − 5².
- 26.Use (a − b)² = a² − 2ab + b² to find 92².
- 27.Use a² − b² = (a + b)(a − b) to find 96² − 57².
- 28.Use (a − b)² = a² − 2ab + b² to find 95².
- 29.If a − b = 2 and ab = 8, what is a² + b²?
- 30.Use (a − b)² = a² − 2ab + b² to find 44².
- 31.Use (a + b)(a − b) = a² − b² to find 98 × 82.
- 32.Use a² − b² = (a + b)(a − b) to find 83² − 17².
- 33.Find the value of x² − y² when x = 9 and y = 2.
- 34.If a − b = 3 and ab = 18, what is a² + b²?
- 35.If a + b = 6 and ab = 5, what is a² + b²?
- 36.Use (a + b)² = a² + 2ab + b² to find 95².
- 37.Use (a + b)(a − b) = a² − b² to find 52 × 48.
- 38.Use a² − b² = (a + b)(a − b) to find 23² − 10².
- 39.Find the value of x² − y² when x = 3 and y = 2.
- 40.Find the value of x² + 2xy + y² when x = 11 and y = 6.
Answer key
- 5041
- 8836
- 7560
- 81
- 1596
- 1225
- 202
- 7047
- 33
- 1024
- 185
- 85
- 1521
- 6561
- 1681
- 143
- 5
- 4864
- 65
- 3969
- 2209
- 130
- 3564
- 301
- 1419
- 8464
- 5967
- 9025
- 20
- 1936
- 8036
- 6600
- 77
- 45
- 26
- 9025
- 2496
- 429
- 5
- 289
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