Question 898109
n, d, q as the variables of each coin.


d=n-5 and q=d+2


Description indicates x for n, or x=n.
{{{d=x-5}}} and {{{q=d+2}}}.
Try substituting for d in the other equation.
{{{q=x-5+2}}}
{{{x=q+5-2}}}
{{{highlight_green(x=q+3)}}}


You still have two equations and three unknown variables.  Some data is missing.