Question 89305

 Problem 1. D= C-S/N (for S)

Problem 2. A=1/2h(B+b)(for b)

    1)  D = C-S/N
        -S/N = D-C
           -S = N(D-C)

            S = -N(D-C) = N(C-D)

            S = N(C-D)



    2)A = 1/2 h(B+b) 

     2A = h(B+b)

     2A/h = B+b

    2A/h - B = b     Therefore  b = (2A/h)-B .