Please show step by step #4b and #5. Thank you

(Section 2.4) 20 points 4. a. Find the diagonal entries of AB by inspection. 4 0 0 6 0 0 A = -2 B = 1 5 - 3 0 7 3 2 6 b. Find a diagonal matrix A, given 9 0 0 A -2 = 0 4 0 10 0 1 (Section 2.5) 20 points 5. Consider an open economy with consumption matrix 1/2 1/4 1/4 C = 1/2 1/8 1/4 1/2 1/ 4 1/8 If the open sector demands the same dollar value from each product-producing sector, which such sector must produce the greatest dollar value to meet the demand? Is the economy productive