Final answer:
The value of 5a² - b² is 10.
Step-by-step explanation:
To find the value of 5a²-b², we can use the identities (a + b)(a - b) = a² - b² and (a + b)² = a² + 2ab + b².
Given that a - b = 1/3 and a + b = 6, we can substitute these values into the identities.
(1/3)(6) = a² - b²
Simplifying gives 2 = a² - b².
Therefore, the value of 5a² - b² is 10.
Learn more about value of a mathematical expression