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 = 11 and y = 10.
- 2.Use (a + b)² = a² + 2ab + b² to find 21².
- 3.Use (a + b)² = a² + 2ab + b² to find 89².
- 4.If a − b = 1 and ab = 2, what is a² + b²?
- 5.Use (a + b)² = a² + 2ab + b² to find 35².
- 6.Use (a + b)² = a² + 2ab + b² to find 91².
- 7.Use a² − b² = (a + b)(a − b) to find 61² − 21².
- 8.Use a² − b² = (a + b)(a − b) to find 36² − 12².
- 9.If a + b = 20 and ab = 96, what is a² + b²?
- 10.Use (a − b)² = a² − 2ab + b² to find 38².
- 11.If a + b = 16 and ab = 55, what is a² + b²?
- 12.Find the value of x² − y² when x = 7 and y = 3.
- 13.Use a² − b² = (a + b)(a − b) to find 33² − 29².
- 14.Use (a + b)(a − b) = a² − b² to find 44 × 36.
- 15.If a + b = 8 and ab = 7, what is a² + b²?
- 16.Use (a + b)² = a² + 2ab + b² to find 11².
- 17.Use (a − b)² = a² − 2ab + b² to find 66².
- 18.Use (a − b)² = a² − 2ab + b² to find 72².
- 19.Use (a + b)² = a² + 2ab + b² to find 22².
- 20.Use (a + b)(a − b) = a² − b² to find 71 × 69.
- 21.Use a² − b² = (a + b)(a − b) to find 84² − 66².
- 22.Use (a − b)² = a² − 2ab + b² to find 39².
- 23.Use a² − b² = (a + b)(a − b) to find 39² − 13².
- 24.Use (a − b)² = a² − 2ab + b² to find 64².
- 25.Use a² − b² = (a + b)(a − b) to find 57² − 28².
- 26.Use (a + b)² = a² + 2ab + b² to find 98².
- 27.Find the value of x² + 2xy + y² when x = 14 and y = 3.
- 28.Use (a − b)² = a² − 2ab + b² to find 83².
- 29.Use a² − b² = (a + b)(a − b) to find 78² − 72².
- 30.Use (a + b)(a − b) = a² − b² to find 49 × 31.
- 31.Use (a + b)² = a² + 2ab + b² to find 26².
- 32.Use (a + b)(a − b) = a² − b² to find 42 × 38.
- 33.Use (a + b)(a − b) = a² − b² to find 93 × 87.
- 34.If a − b = 3 and ab = 10, what is a² + b²?
- 35.Use a² − b² = (a + b)(a − b) to find 26² − 11².
- 36.Use (a + b)² = a² + 2ab + b² to find 17².
- 37.Find the value of x² + 2xy + y² when x = 6 and y = 3.
- 38.Use (a − b)² = a² − 2ab + b² to find 93².
- 39.Use a² − b² = (a + b)(a − b) to find 49² − 9².
- 40.Use (a − b)² = a² − 2ab + b² to find 97².
Answer key
- 1
- 441
- 7921
- 5
- 1225
- 8281
- 3280
- 1152
- 208
- 1444
- 146
- 40
- 248
- 1584
- 50
- 121
- 4356
- 5184
- 484
- 4899
- 2700
- 1521
- 1352
- 4096
- 2465
- 9604
- 289
- 6889
- 900
- 1519
- 676
- 1596
- 8091
- 29
- 555
- 289
- 81
- 8649
- 2320
- 9409
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