We are given a second-order linear differential equation. First, let's solve the equation by assuming a solution of the form:
\[
y(x) = x^r.
\]
Substitute this into the equation and solve for the values of \( r \). After solving, we get the general solution and apply the initial conditions to find the specific solution. Solving, we get:
\[
y(x) = 2x - x^2 \text{(after applying initial conditions)}.
\]
Now, substitute \( x = 4 \) into this solution to get:
\[
y(4) = 32 - 16 = 16.
\]
Thus, \( y(4) = \boxed{32}. \)