closed loop poles and feedback coefficient matrix

I have a matrix equ:
syms y1 y2 y3 y4 y5 y6 y7 y8 y9 y10 y11 y12

Ydot = Ay + Bu +H
y=[ y2 y3 y4 y5 y6 y67 y8 y9 y10 y11]'
u=[u2 u3 u4]'

Can someone help me to determine the closed loop poles and feedback coefficient matrix when k =1.

A= [k 0 0 0 0 0 0 0 0 0 0;...
0 k 0 0 0 0 0 0 0 0 0;...
0 0 k 0 0 0 0 0 0 0 0;...
0 0 0 k 0 0 0 0 0 0 0;...
0 0 0 0 k 0 0 0 0 0 0;...
0 0 0 0 0 k 0 0 0 0 0;...
0 0 0 0 0 0 k 0 0 0 0;...
0 0 0 0 0 0 0 k 0 0 0;...
0 0 0 0 0 0 0 0 k 0 0;...
0 0 0 0 0 0 0 0 0 k 0;...
0 0 0 0 0 0 0 0 0 0 ];

B= [0 0 0;...
0 0 0;...
0 0 0;...
0 0 0;...
0 0 0;...
0 0 0;...
1/y1 0 0;...
0 0 0;...
0 1/y1 0;...
0 0 0;...
0 0 1/y1];

H= [0;...
y1*y4;...
0;...
y1*y6;...
0;...
y1*y8;...
1;...
y1*y10;...
0;...
y1*y12;...
0];


Thank you very much.