Final answer:
To find f(x), we integrate f'(x) = 7 / x^4 and use f(1) = 4 to determine the constant of integration. The correct answer is D. f(x) = -7 / 3 x^-3 + 13 / 3.
Step-by-step explanation:
To find f(x) given f'(x) = 7 / x^4 and f(1) = 4, we can use the equation f(x) = ∫f'(x) dx. Integrating the given derivative, we get:
f(x) = -7 / 3x^3 + C
Substituting x = 1 and f(1) = 4, we can solve for C and find the final equation:
f(x) = -7 / 3x^3 + 13 / 3
Hence, the correct answer is D. f(x) = -7 / 3 x^-3 + 13 / 3.