Answer :
You multiply the 3 by -6 then multiply the 3 by 6 , one you get -18 and the other you 18x you change the -18 into a positive then add it by 18 in get 36 then you divide by 18x in get 2

3(-6+6x)=18
multiply the bracket by 3
(3)(-6)=-18
(3)(6x)=18x
-18+18x=18
move -18 to the other side
sign changes from -18 to +18
-18+18x+18=18+18
-18+18+18x=18+18 ( rearranging)
18x=36
divide both sides by 18 to get x by itself
18x/18=36/18
answer:
x=2