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 − y² when x = 9 and y = 2.
- 2.Find the value of x² − y² when x = 3 and y = 2.
- 3.Find the value of x² − y² when x = 5 and y = 3.
- 4.Find the value of x² + 2xy + y² when x = 13 and y = 2.
- 5.Find the value of x² − y² when x = 6 and y = 5.
- 6.Use (a + b)² = a² + 2ab + b² to find 37².
- 7.Find the value of x² − y² when x = 7 and y = 4.
- 8.Use (a − b)² = a² − 2ab + b² to find 41².
- 9.Use (a + b)² = a² + 2ab + b² to find 81².
- 10.If a − b = 1 and ab = 6, what is a² + b²?
- 11.Use (a + b)(a − b) = a² − b² to find 107 × 93.
- 12.Find the value of x² − y² when x = 14 and y = 13.
- 13.Use (a + b)² = a² + 2ab + b² to find 62².
- 14.Use (a − b)² = a² − 2ab + b² to find 17².
- 15.Use (a + b)(a − b) = a² − b² to find 62 × 58.
- 16.Find the value of x² + 2xy + y² when x = 12 and y = 1.
- 17.Find the value of x² + 2xy + y² when x = 5 and y = 1.
- 18.If a + b = 12 and ab = 35, what is a² + b²?
- 19.Find the value of x² − y² when x = 11 and y = 9.
- 20.Use (a + b)(a − b) = a² − b² to find 35 × 25.
- 21.Use (a + b)(a − b) = a² − b² to find 68 × 52.
- 22.Use (a + b)² = a² + 2ab + b² to find 71².
- 23.Use a² − b² = (a + b)(a − b) to find 61² − 5².
- 24.If a + b = 5 and ab = 6, what is a² + b²?
- 25.Use (a − b)² = a² − 2ab + b² to find 73².
- 26.Use (a + b)² = a² + 2ab + b² to find 99².
- 27.Use (a + b)² = a² + 2ab + b² to find 34².
- 28.Use (a + b)(a − b) = a² − b² to find 33 × 27.
- 29.Use (a + b)(a − b) = a² − b² to find 59 × 41.
- 30.Use a² − b² = (a + b)(a − b) to find 65² − 38².
- 31.Find the value of x² − y² when x = 13 and y = 2.
- 32.Use (a + b)² = a² + 2ab + b² to find 54².
- 33.If a − b = 2 and ab = 120, what is a² + b²?
- 34.Use (a + b)(a − b) = a² − b² to find 98 × 82.
- 35.Use (a + b)(a − b) = a² − b² to find 58 × 42.
- 36.If a − b = 1 and ab = 20, what is a² + b²?
- 37.Use (a + b)² = a² + 2ab + b² to find 96².
- 38.Use a² − b² = (a + b)(a − b) to find 81² − 56².
- 39.Find the value of x² + 2xy + y² when x = 4 and y = 1.
- 40.Find the value of x² + 2xy + y² when x = 7 and y = 2.
Answer key
- 77
- 5
- 16
- 225
- 11
- 1369
- 33
- 1681
- 6561
- 13
- 9951
- 27
- 3844
- 289
- 3596
- 169
- 36
- 74
- 40
- 875
- 3536
- 5041
- 3696
- 13
- 5329
- 9801
- 1156
- 891
- 2419
- 2781
- 165
- 2916
- 244
- 8036
- 2436
- 41
- 9216
- 3425
- 25
- 81
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