Let h={x in R^n | c1x1+....+cnxn+d=0} (atleast one of the c's is nonzero)

Let T:R^n-->R be defined as Tx=Ax,where A=[c1...cn] (and c's are the columns of martix A) and x in R^n...Then T is a linear transformation..

My question is that is matrix A= a11....a1n

a21....a2n

an1....ann

That means matrix A is a n*n matrix...But the way the map is defined T:R^n-->R implies that A is a 1*n matrix..