p1(x) = x^2 - 9, p2(x) = x + 3, p3(x) = x- 3. Show that p1(A)=p2(A)p3(A).

A = 2 0

4 1

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I inserted the equation times the matrix A and then noticed p1(A) = (p2*p3)(A) and then decided to cancel A's. Which left only the equations and then it's obvious that by foiling p2*p3 you get p1. Way too easy. What am I missing?