-6*a=15

7*a-3*b=-68.1
2*a+7*b=-11.6

4*a-3*b+6*c=-41.5
5*a+4*b-9*c=-31.6
-9*a+5*b+9*c=71.9

-6*a+5*b-7*c-6*d=-16.7
-6*a+2*b-7*c+9*d=53.8
-8*a-5*b-4*c-5*d=8.5
8*a+6*b+8*c-9*d=-81.3

-5*a-5*b-7*c-8*d+9*e=115.4
8*a+7*b-4*c+9*d+6*e=69.4
-3*a+5*b-8*c-6*d-2*e=-30.8
4*a+2*b-7*c-2*d+2*e=70.2
-3*a+2*b-5*c+5*d+2*e=-28