solve

bool isConsiderZeroTolerant(T) (T f) nothrow
{
    return (abs(f) < 0.0001f);
}

Matrix3f a = matrixf(
    1, 3, -2,
    3, 5,  6,
    2, 4,  3
);
Vector3f b = Vector3f(5, 7, 8);
Vector3f x = Vector3f(0, 0, 0);

solve(a, x, b);

assert(isConsiderZeroTolerant(-15 - x[0]));
assert(isConsiderZeroTolerant(8 - x[1]));
assert(isConsiderZeroTolerant(2 - x[2]));