syms N1 N2 N3
a=0.0640;
b=-0.7629;
c=-0.0936;
x1=xlsread('F:\data 1.xlsx', 'C2:C9');
x2=xlsread('F:\data 1.xlsx', 'G2:G9');
x3=xlsread('F:\data 1.xlsx', 'F2:F9');
y=xlsread('F:\data 1.xlsx', 'B2:B9');
QUE=y-((a.*x1+b.*(x2.^(1/2))+c.*x3).*(1-(x1./N1)-((x2.^(1/2))./N2)-(x3./N3)));
[N1,N2,N3]=solve(QUE,N1,N2,N3)