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 61².
- 2.Use (a + b)² = a² + 2ab + b² to find 61².
- 3.If a + b = 7 and ab = 12, what is a² + b²?
- 4.Use (a + b)² = a² + 2ab + b² to find 77².
- 5.Use (a + b)(a − b) = a² − b² to find 79 × 61.
- 6.Use (a − b)² = a² − 2ab + b² to find 93².
- 7.Use (a − b)² = a² − 2ab + b² to find 32².
- 8.If a + b = 18 and ab = 77, what is a² + b²?
- 9.If a + b = 15 and ab = 44, what is a² + b²?
- 10.Use (a + b)(a − b) = a² − b² to find 61 × 59.
- 11.If a + b = 5 and ab = 6, what is a² + b²?
- 12.Find the value of x² + 2xy + y² when x = 15 and y = 9.
- 13.Use (a − b)² = a² − 2ab + b² to find 29².
- 14.Use (a + b)² = a² + 2ab + b² to find 67².
- 15.Use (a + b)(a − b) = a² − b² to find 62 × 58.
- 16.Use (a + b)² = a² + 2ab + b² to find 27².
- 17.Find the value of x² − y² when x = 8 and y = 1.
- 18.Use (a + b)² = a² + 2ab + b² to find 35².
- 19.Use (a + b)(a − b) = a² − b² to find 93 × 87.
- 20.If a − b = 8 and ab = 20, what is a² + b²?
- 21.Use (a − b)² = a² − 2ab + b² to find 66².
- 22.Find the value of x² − 2xy + y² when x = 15 and y = 6.
- 23.Use a² − b² = (a + b)(a − b) to find 52² − 22².
- 24.Find the value of x² − y² when x = 3 and y = 1.
- 25.If a − b = 1 and ab = 2, what is a² + b²?
- 26.If a + b = 6 and ab = 5, what is a² + b²?
- 27.Find the value of x² + 2xy + y² when x = 14 and y = 1.
- 28.Find the value of x² + 2xy + y² when x = 8 and y = 5.
- 29.Use (a + b)² = a² + 2ab + b² to find 11².
- 30.Use (a + b)² = a² + 2ab + b² to find 72².
- 31.If a + b = 3 and ab = 2, what is a² + b²?
- 32.If a − b = 1 and ab = 12, what is a² + b²?
- 33.Find the value of x² + 2xy + y² when x = 3 and y = 2.
- 34.Find the value of x² + 2xy + y² when x = 8 and y = 1.
- 35.Find the value of x² − y² when x = 10 and y = 6.
- 36.Use (a − b)² = a² − 2ab + b² to find 16².
- 37.Use (a + b)² = a² + 2ab + b² to find 13².
- 38.Use a² − b² = (a + b)(a − b) to find 77² − 65².
- 39.Use (a + b)² = a² + 2ab + b² to find 71².
- 40.Use a² − b² = (a + b)(a − b) to find 61² − 52².
Answer key
- 3721
- 3721
- 25
- 5929
- 4819
- 8649
- 1024
- 170
- 137
- 3599
- 13
- 576
- 841
- 4489
- 3596
- 729
- 63
- 1225
- 8091
- 104
- 4356
- 81
- 2220
- 8
- 5
- 26
- 225
- 169
- 121
- 5184
- 5
- 25
- 25
- 81
- 64
- 256
- 169
- 1704
- 5041
- 1017
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