Question 621032
{{{C=(1/2)*M(S+Z)}}}


{{{2C=M(S+Z)}}}


{{{2C=MS+MZ}}}


{{{2C-MZ=MS}}}


{{{(2C-MZ)/M=S}}}


{{{S = (2C-MZ)/M}}}


So the solution is {{{S = (2C-MZ)/M}}}