Hi, 1.Show that B satisfies the equation (B-pI)(B-qI) = 0 2.Hence, or otherwise, show that B-1 = 0.5(3I - B) In these kind of questions I don't know what they are testing me for! Let's take the first one as an example: The only skill they can possibly try to asses is whether I know how to multiply the matrix I by values I found previously (p and q). Other than that, all I can do to "answer" the question is performing the multiplication and showing it equals zero? For the second one it is even worst... I know how to calculate the inverse of B and when I do it does in fact equal 0.5(3I - B), but, what should I put on paper? Calculate the inverse the regular way and then perform 0.5(3I - B) and show the results are equal? I'm not sure if I was able to convey my doubt clearly... If the problem is due to lack of information in questions 1 and 2 I can add more information or rephrase my query. Thanks, Peter G.