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 = 7 and y = 2.
- 2.Use (a − b)² = a² − 2ab + b² to find 47².
- 3.Find the value of x² − 2xy + y² when x = 11 and y = 3.
- 4.Use a² − b² = (a + b)(a − b) to find 37² − 16².
- 5.Use (a + b)(a − b) = a² − b² to find 94 × 86.
- 6.Use a² − b² = (a + b)(a − b) to find 75² − 35².
- 7.Use (a + b)² = a² + 2ab + b² to find 32².
- 8.If a + b = 9 and ab = 18, what is a² + b²?
- 9.Use (a + b)² = a² + 2ab + b² to find 22².
- 10.Use a² − b² = (a + b)(a − b) to find 37² − 4².
- 11.Use (a + b)² = a² + 2ab + b² to find 28².
- 12.Use (a − b)² = a² − 2ab + b² to find 81².
- 13.Use a² − b² = (a + b)(a − b) to find 60² − 18².
- 14.Find the value of x² + 2xy + y² when x = 14 and y = 3.
- 15.Use (a − b)² = a² − 2ab + b² to find 33².
- 16.Use (a + b)² = a² + 2ab + b² to find 87².
- 17.If a + b = 9 and ab = 14, what is a² + b²?
- 18.Use (a − b)² = a² − 2ab + b² to find 96².
- 19.Use (a + b)(a − b) = a² − b² to find 58 × 42.
- 20.Use (a + b)(a − b) = a² − b² to find 62 × 58.
- 21.Use (a − b)² = a² − 2ab + b² to find 13².
- 22.Use (a + b)(a − b) = a² − b² to find 75 × 65.
- 23.Use a² − b² = (a + b)(a − b) to find 76² − 50².
- 24.If a − b = 2 and ab = 3, what is a² + b²?
- 25.Find the value of x² − y² when x = 5 and y = 1.
- 26.Use a² − b² = (a + b)(a − b) to find 79² − 12².
- 27.Use (a + b)(a − b) = a² − b² to find 86 × 74.
- 28.Find the value of x² + 2xy + y² when x = 6 and y = 1.
- 29.Use a² − b² = (a + b)(a − b) to find 54² − 33².
- 30.Use (a + b)(a − b) = a² − b² to find 79 × 61.
- 31.If a + b = 6 and ab = 5, what is a² + b²?
- 32.Use (a − b)² = a² − 2ab + b² to find 16².
- 33.Use (a + b)(a − b) = a² − b² to find 91 × 89.
- 34.Use a² − b² = (a + b)(a − b) to find 35² − 34².
- 35.Find the value of x² − y² when x = 12 and y = 6.
- 36.Use (a − b)² = a² − 2ab + b² to find 43².
- 37.Use (a − b)² = a² − 2ab + b² to find 18².
- 38.Use a² − b² = (a + b)(a − b) to find 35² − 33².
- 39.If a − b = 7 and ab = 30, what is a² + b²?
- 40.Use (a + b)² = a² + 2ab + b² to find 39².
Answer key
- 45
- 2209
- 64
- 1113
- 8084
- 4400
- 1024
- 45
- 484
- 1353
- 784
- 6561
- 3276
- 289
- 1089
- 7569
- 53
- 9216
- 2436
- 3596
- 169
- 4875
- 3276
- 10
- 24
- 6097
- 6364
- 49
- 1827
- 4819
- 26
- 256
- 8099
- 69
- 108
- 1849
- 324
- 136
- 109
- 1521
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