【答案】应助回帖

% (1)
info = 'STUDY AND ONCE MORE STUDY';
W = abs(info);
A = reshape(W,5,5);

%(2)
Q = eye(5);
% r1
x = Q(2,:);
Q(2,:) = Q(3,:);
Q(3,:) = x;
% r3,k=2
k = 2;
Q(4,:) = Q(4,:)+Q(1,:)*k;
invQ = inv(Q);

%(3)
B = Q*A;
C = invQ*B;
D = reshape(char(C),1,numel(C));
disp(D);

STUDY AND ONCE MORE STUDY
>>