Solve the differential equation dy/dx = 5-y?

that's a separable DE..
dy/5-y=dx
ln(y-5) = x+K => take e^(each side) 
y-5 = e^(x+K) = e^(x)*e^(K) => Redefine e^K = C 
y-5 = C*e^(t) => Add 5 to both sides 
y=C*e^(x) + 5 =>

When i did the math i got 11 cm