to find x you have to set 3x+1 and 4x-5 equal to each other
3x+1=4x-5
you then subtract 3x from 4x to get 1x
1=1x-5
then add 5 to the 1 on the other side of the equal side
6=1x
divide by 1 to get the x by itself and you end up with x=6
after this to find the values of the segments you plug 6 in for x
AB= 3(6)+1
BC= 4(6)-5
and AC= 8(6)-9 or you can add the answer from AB and BC together to check your answer for BC
I HOPE THIS HELPS