Question 127120
One number is x, and the other is y.


x is 12 more than y:  {{{x=y+12}}}


The smaller number, y, plus twice the larger number, x, is 39:


{{{y + 2x = 39}}}


Substituting:
{{{y+2(y+12)=39}}}
{{{3y+24=39}}}
{{{3y=15}}}
{{{y=5}}}


Since y = 5, x must be 5 + 12 = 17.


Check: 5 + 2(17) = 5 + 34 = 39. Answer checks.