Question 1154066
{{{(x+2)+(3x+1)+(x+7)=140}}}


{{{5x+10=140}}}


{{{x+2=28}}}


{{{x=26}}}---------------this may mean the side lengths are 28, 79, and 33.

Check to be sure each of these is true:
{{{system(28+79>33,79+33>28,28+33>79)}}}
If any is false, then the triangle with those sides is no good.