if A=[2 -2 -4 is an idempotent matrix ,then x is equal to? -1 3 4 1 2 x] a)-5 b)-1 c)-3 d)-4 Share with your friends Share 0 Rishabh Mittal answered this You have writen the element in 3rd row and 2nd column wrong.it will be -2 not 2.A=2-2-4-1341-2xFor idempotent matrix,AA=ASo,2-2-4-1341-2x2-2-4-1341-2x=2-2-4-1341-2x4+2-4-4-6+8-8-8-4x-2-3+42+9-84+12+4x2+2+x-2-6-2x-4-8+x2=2-2-4-1341-2x2-2-16-4x-1316+4x4+x-8-2x-12+x2=2-2-4-1341-2xComparing LHS and RHS , we get-16-4x=-4-4x=12x=-3. ANS... 0 View Full Answer