If a rank is a number associated with a matrix which is the highest order of non-singular sub matrix that prove that
(i) Rank of the matrix `A=[{:(,1,3,-2),(,4,-1,0),(,2,-7,4):}]"is "2`
(ii)If the matrix `A=[{:(,y+a,b,c),(,a,y+b,c),(,a,b,y+c):}]` has rank 4, then `y ne -(a+b+c) and y ne 0`
(iii) If A & B are two square matrices of order 3 such that rank of matrix AB is two. then atleast one of A&B is singular.