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 = 8 and y = 5.
- 2.Find the value of x² − y² when x = 11 and y = 4.
- 3.Use (a + b)² = a² + 2ab + b² to find 91².
- 4.Find the value of x² − 2xy + y² when x = 9 and y = 1.
- 5.Use (a − b)² = a² − 2ab + b² to find 48².
- 6.Use a² − b² = (a + b)(a − b) to find 98² − 78².
- 7.Use a² − b² = (a + b)(a − b) to find 72² − 52².
- 8.Use a² − b² = (a + b)(a − b) to find 61² − 39².
- 9.Use (a + b)(a − b) = a² − b² to find 48 × 32.
- 10.Use (a − b)² = a² − 2ab + b² to find 24².
- 11.Find the value of x² − 2xy + y² when x = 5 and y = 4.
- 12.Use a² − b² = (a + b)(a − b) to find 67² − 18².
- 13.Use (a + b)(a − b) = a² − b² to find 94 × 86.
- 14.Use (a − b)² = a² − 2ab + b² to find 41².
- 15.Use (a + b)² = a² + 2ab + b² to find 97².
- 16.Find the value of x² − y² when x = 13 and y = 4.
- 17.If a + b = 11 and ab = 30, what is a² + b²?
- 18.Use (a + b)² = a² + 2ab + b² to find 101².
- 19.Use (a + b)² = a² + 2ab + b² to find 42².
- 20.Use a² − b² = (a + b)(a − b) to find 58² − 12².
- 21.Find the value of x² + 2xy + y² when x = 13 and y = 10.
- 22.Use (a + b)(a − b) = a² − b² to find 104 × 96.
- 23.Use (a + b)² = a² + 2ab + b² to find 38².
- 24.Find the value of x² − 2xy + y² when x = 14 and y = 7.
- 25.Use (a + b)(a − b) = a² − b² to find 37 × 23.
- 26.Use (a − b)² = a² − 2ab + b² to find 93².
- 27.Find the value of x² − y² when x = 9 and y = 2.
- 28.Use (a + b)² = a² + 2ab + b² to find 74².
- 29.Use (a − b)² = a² − 2ab + b² to find 44².
- 30.Use (a + b)² = a² + 2ab + b² to find 13².
- 31.Use (a + b)² = a² + 2ab + b² to find 58².
- 32.Use a² − b² = (a + b)(a − b) to find 45² − 22².
- 33.Use (a + b)² = a² + 2ab + b² to find 68².
- 34.Use (a − b)² = a² − 2ab + b² to find 47².
- 35.Use (a − b)² = a² − 2ab + b² to find 15².
- 36.If a − b = 1 and ab = 2, what is a² + b²?
- 37.Use (a + b)(a − b) = a² − b² to find 35 × 25.
- 38.Use (a + b)(a − b) = a² − b² to find 105 × 95.
- 39.If a + b = 14 and ab = 24, what is a² + b²?
- 40.Use (a − b)² = a² − 2ab + b² to find 89².
Answer key
- 169
- 105
- 8281
- 64
- 2304
- 3520
- 2480
- 2200
- 1536
- 576
- 1
- 4165
- 8084
- 1681
- 9409
- 153
- 61
- 10201
- 1764
- 3220
- 529
- 9984
- 1444
- 49
- 851
- 8649
- 77
- 5476
- 1936
- 169
- 3364
- 1541
- 4624
- 2209
- 225
- 5
- 875
- 9975
- 148
- 7921
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