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.Find the value of x² − 2xy + y² when x = 7 and y = 1.
- 2.If a + b = 14 and ab = 40, what is a² + b²?
- 3.Use a² − b² = (a + b)(a − b) to find 56² − 21².
- 4.Use a² − b² = (a + b)(a − b) to find 61² − 7².
- 5.If a + b = 14 and ab = 48, what is a² + b²?
- 6.If a − b = 2 and ab = 3, what is a² + b²?
- 7.Use (a − b)² = a² − 2ab + b² to find 34².
- 8.Use (a + b)(a − b) = a² − b² to find 64 × 56.
- 9.Use (a − b)² = a² − 2ab + b² to find 11².
- 10.If a + b = 9 and ab = 20, what is a² + b²?
- 11.Use (a + b)² = a² + 2ab + b² to find 17².
- 12.If a + b = 16 and ab = 63, what is a² + b²?
- 13.Find the value of x² + 2xy + y² when x = 12 and y = 8.
- 14.Use a² − b² = (a + b)(a − b) to find 22² − 3².
- 15.Use a² − b² = (a + b)(a − b) to find 24² − 13².
- 16.Use a² − b² = (a + b)(a − b) to find 84² − 18².
- 17.Use (a + b)(a − b) = a² − b² to find 56 × 44.
- 18.Use (a − b)² = a² − 2ab + b² to find 74².
- 19.Use a² − b² = (a + b)(a − b) to find 62² − 27².
- 20.Use (a − b)² = a² − 2ab + b² to find 71².
- 21.Find the value of x² + 2xy + y² when x = 3 and y = 2.
- 22.If a + b = 9 and ab = 18, what is a² + b²?
- 23.Find the value of x² − y² when x = 13 and y = 8.
- 24.Use (a − b)² = a² − 2ab + b² to find 89².
- 25.Find the value of x² + 2xy + y² when x = 15 and y = 5.
- 26.Use (a + b)(a − b) = a² − b² to find 99 × 81.
- 27.Use a² − b² = (a + b)(a − b) to find 31² − 6².
- 28.If a + b = 9 and ab = 8, what is a² + b²?
- 29.If a − b = 4 and ab = 12, what is a² + b²?
- 30.Use (a − b)² = a² − 2ab + b² to find 16².
- 31.Find the value of x² + 2xy + y² when x = 4 and y = 1.
- 32.Use (a + b)(a − b) = a² − b² to find 93 × 87.
- 33.Use (a + b)² = a² + 2ab + b² to find 12².
- 34.Use (a + b)(a − b) = a² − b² to find 83 × 77.
- 35.Use a² − b² = (a + b)(a − b) to find 27² − 4².
- 36.Use a² − b² = (a + b)(a − b) to find 57² − 35².
- 37.Use (a + b)(a − b) = a² − b² to find 39 × 21.
- 38.Use (a + b)(a − b) = a² − b² to find 43 × 37.
- 39.Use a² − b² = (a + b)(a − b) to find 80² − 8².
- 40.Use (a − b)² = a² − 2ab + b² to find 37².
Answer key
- 36
- 116
- 2695
- 3672
- 100
- 10
- 1156
- 3584
- 121
- 41
- 289
- 130
- 400
- 475
- 407
- 6732
- 2464
- 5476
- 3115
- 5041
- 25
- 45
- 105
- 7921
- 400
- 8019
- 925
- 65
- 40
- 256
- 25
- 8091
- 144
- 6391
- 713
- 2024
- 819
- 1591
- 6336
- 1369
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