jmc

We can substitute the second equation into the first equation to get $$s=9-2(3s+1)=9-6s-2.$$Moving the variable terms to the left-hand side and the constants to the right-hand side, we find $$s+6s=7.$$This gives $s=1$ which we may plug into either equation to get $t$. For example, $$t=3(1)+1=4.$$So the lines intersect at the point $\boxed{(1,4)}$.