Solving Normal Equations With Matlab

I have 9 values for s and So.How can i find the parameters a0,a1 a2 of the following normal equations using Matlab?

(1) a0*n+a1*Sum(So)+a2*Sum(So^2)=Sum(s)

(2) a0*Sum(So)+a1*Sum(So^2)+a2*Sum(So^3)=Sum(s*So)

(3) a0*Sum(So^2)+a1*Sum(So^3)+ a2*Sum(So^4)=Sum(s*So*So^2)

*The Sums are for i=1 to n=9