Question 955263
{{{D+A=25}}}
.
.
.
{{{(D-5)=4(A-5)}}}
{{{D-5=4A-20}}}
{{{D-4A=-15}}}
Subtracting eq. 1 from eq. 2,
{{{D-4A-D-A=-15-25}}}
{{{-5A=-40}}}
{{{A=8}}}
Then,
{{{D+8=25}}}
{{{D=17}}}