[tex]Solution,solve\:for\:d,\:d-10-2d+7=8+d-10-3d\quad :\quad d=1[/tex]
[tex]Steps:[/tex]
[tex]d-10-2d+7=8+d-10-3d[/tex]
[tex]\mathrm{Subtract\:}d-10\mathrm{\:from\:both\:sides},\\d-10-2d+7-\left(d-10\right)=8+d-10-3d-\left(d-10\right)[/tex]
[tex]\mathrm{Refine},\\-2d+7=8-3d[/tex]
[tex]\mathrm{Subtract\:}7\mathrm{\:from\:both\:sides},\\-2d+7-7=8-3d-7[/tex]
[tex]\mathrm{Simplify},\\-2d=-3d+1[/tex]
[tex]\mathrm{Add\:}3d\mathrm{\:to\:both\:sides},\\-2d+3d=-3d+1+3d[/tex]
[tex]\mathrm{Simplify},\\d=1[/tex]
[tex]\mathrm{The\:Correct\:Answer\:is\:d=1}[/tex]
[tex]\mathrm{Hope\:This\:Helps!!!}[/tex]
[tex]\mathrm{-Austint1414}[/tex]