If f(x) = 10x + 7 and g(x) = x^2 - 7x, find (f - g)(x)

A. (f - g)(x) = x^2 + 3x + 7
B. (f - g)(x) = 10x^3 - 63x^2 - 49x
C. (f - g)(x) = -x^2 + 17x + 7
D. (f - g)(x) = 10x + 7