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)(a − b) = a² − b² to find 23 × 17.
- 3.Use (a + b)(a − b) = a² − b² to find 53 × 47.
- 4.Use (a − b)² = a² − 2ab + b² to find 22².
- 5.Use (a + b)² = a² + 2ab + b² to find 38².
- 6.Use (a + b)(a − b) = a² − b² to find 93 × 87.
- 7.Use (a + b)(a − b) = a² − b² to find 31 × 29.
- 8.Find the value of x² − 2xy + y² when x = 9 and y = 1.
- 9.Use (a + b)(a − b) = a² − b² to find 69 × 51.
- 10.Use (a − b)² = a² − 2ab + b² to find 72².
- 11.If a + b = 17 and ab = 60, what is a² + b²?
- 12.Use (a + b)(a − b) = a² − b² to find 58 × 42.
- 13.If a − b = 5 and ab = 6, what is a² + b²?
- 14.Use (a − b)² = a² − 2ab + b² to find 13².
- 15.Find the value of x² + 2xy + y² when x = 6 and y = 4.
- 16.Use a² − b² = (a + b)(a − b) to find 60² − 24².
- 17.Use (a + b)² = a² + 2ab + b² to find 85².
- 18.Use (a + b)² = a² + 2ab + b² to find 71².
- 19.Use a² − b² = (a + b)(a − b) to find 65² − 35².
- 20.Find the value of x² − 2xy + y² when x = 7 and y = 3.
- 21.Use (a + b)² = a² + 2ab + b² to find 91².
- 22.Use (a + b)² = a² + 2ab + b² to find 27².
- 23.Find the value of x² + 2xy + y² when x = 15 and y = 7.
- 24.Use (a − b)² = a² − 2ab + b² to find 91².
- 25.If a − b = 1 and ab = 6, what is a² + b²?
- 26.Use (a + b)² = a² + 2ab + b² to find 14².
- 27.Use a² − b² = (a + b)(a − b) to find 37² − 26².
- 28.Use (a + b)² = a² + 2ab + b² to find 52².
- 29.Use a² − b² = (a + b)(a − b) to find 84² − 9².
- 30.Use (a + b)(a − b) = a² − b² to find 88 × 72.
- 31.If a + b = 3 and ab = 2, what is a² + b²?
- 32.Use (a − b)² = a² − 2ab + b² to find 31².
- 33.Use (a − b)² = a² − 2ab + b² to find 56².
- 34.If a + b = 10 and ab = 24, what is a² + b²?
- 35.Use (a + b)(a − b) = a² − b² to find 27 × 13.
- 36.Find the value of x² − 2xy + y² when x = 11 and y = 10.
- 37.Find the value of x² − 2xy + y² when x = 11 and y = 3.
- 38.Use a² − b² = (a + b)(a − b) to find 77² − 68².
- 39.If a − b = 4 and ab = 32, what is a² + b²?
- 40.Use a² − b² = (a + b)(a − b) to find 98² − 96².
Answer key
- 3721
- 391
- 2491
- 484
- 1444
- 8091
- 899
- 64
- 3519
- 5184
- 169
- 2436
- 37
- 169
- 100
- 3024
- 7225
- 5041
- 3000
- 16
- 8281
- 729
- 484
- 8281
- 13
- 196
- 693
- 2704
- 6975
- 6336
- 5
- 961
- 3136
- 52
- 351
- 1
- 64
- 1305
- 80
- 388
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