Let a be a matrix of order n, satisfy 2A ^ 2-3a + 5I = 0, and prove (a-3i) = - 1 / 14 (2a + 3I) speed

Let a be a matrix of order n, satisfy 2A ^ 2-3a + 5I = 0, and prove (a-3i) = - 1 / 14 (2a + 3I) speed


Because 2A ^ 2-3a + 5I = 0
So 2A (a-3i) + 3 (a-3i) + 14i = 0
So (2a + 3I) (a-3i) = - 14i
So (a-3i) ^ - 1 = (- 1 / 14) (2a + 3I)