Question 176195
I think you meant {{{M = (S - C)/S}}}


Solve for S:


Multiply both sides by S:


{{{SM = S - C}}}


Add -S to both sides:


{{{SM - S = -C}}}


Multiply both sides by -1:


{{{-SM + S = C}}}


{{{S - SM = C}}}


Factor the left:


{{{S ( 1 - M ) = C}}}


Divide by {{{1 - M}}}


{{{S = C/(1 - M)}}}