Solving for coefficients : Substitution error

In the below matlab code, I m solving for the coefficients b,c,d,e,f by comparing to a known equation. In the second last line of the code, I get d which is a function of b and c. I want to substitute the values of b and c obtained in the third last line and fourth last line to get a constant value of d. How should I do it. The below code is showing an error due to last line.

syms x b c d e f kpc
s1 = -0.45+ 0.35i               
s2 = -0.45 -0.35i         
DomiPoles = expand((x+s1)*(x+s2))
N=0.36111*kpc + 225.0*x + 1.0*kpc*x + 1.1111*kpc*x^2 + 606.96*x^2 + 799.0*x^3 + 444.0*x^4 + 127.0*x^5 + 18.0*x^6 + 1.0*x^7 + 27.455
h= expand(DomiPoles*(x^5 + b*x^4 + c*x^3 +  d*x^2 + e*x + f))
C = coeffs(N - h,x)
b =solve(C(7),b)
c = subs(solve(C(6),c),b)
d = solve(C(5),d)
d = subs(solve(C(5),d),[b, c],[b,c])

Answer 1

[KSSV]

syms x b c d e f kpc
s1 = -0.45+ 0.35i               
s2 = -0.45 -0.35i         
DomiPoles = expand((x+s1)*(x+s2))
N=0.36111*kpc + 225.0*x + 1.0*kpc*x + 1.1111*kpc*x^2 + 606.96*x^2 + 799.0*x^3 + 444.0*x^4 + 127.0*x^5 + 18.0*x^6 + 1.0*x^7 + 27.455
h= expand(DomiPoles*(x^5 + b*x^4 + c*x^3 +  d*x^2 + e*x + f))
C = coeffs(N - h,x)
b =solve(C(7),b)
c = subs(solve(C(6),c),b)
d = solve(C(5),d)
d = subs(d,[b, c],[b,c])

[Rakesh Jain]

The error is not coming now but the Values of b and c are not getting substituted in d by the above code. The output still shows d in terms of b and c only. I want to substitute the values of b and c obtained in the third last line and fourth last line to get a constant value of d