If a + b = 12 and ab = 35, then (a − b)² =

1. 2

2. 4

3. 16

4. 20

Given,

a + b = 12 and ab = 35

Using identity,

⇒ (a + b)² - (a - b)² = 4ab

⇒ (a − b)² = (a + b)² - 4ab

⇒ (a − b)² = (12)² - 4(35)

⇒ (a − b)² = 144 - 140

⇒ (a − b)² = 4

Hence, Option 2 is the correct option.