Final answer:
To find f(a) given f(x) = 5x² - 2x + 4, you substitute 'a' in place of 'x', which results in f(a) = 5a² - 2a + 4, making option d) the correct answer.
Step-by-step explanation:
To find f(a), you simply replace every occurrence of x in the function with a. So, substituting a for x in the original function f(x), we get f(a) = 5a² - 2a + 4. This means that the correct answer is d) f(x) = 5a² - 2a + 4. This process enables a clear understanding of the function's behavior for any given a. The output is a distinct algebraic expression, capturing the essence of the original function for the specified input, thus illustrating how the function behaves uniquely as a variable.