in six years means everybody +6 j+6 is 4 times (l+6) j+6=4(l+6)
the equations are j=6s s=2+l j+6=4(l+6)
you would subisutte 6s+6=4(l+6) 6(2+l)+6=4(l+6) undistribute the 2 in each 2(3(2+l)+3)=2(2(l+6)) divide both sides by 2 3(2+l)+3=2(l+6) distribute 6+3l+3=2l+12 add like terms 9+3l=2l+12 subtract 9 from both sides 3l=2l+3 subtract 2l from both sides l=3