so first we distribute 1/3(9a-18) a three can be factored out of (9a-18)=3(3a-6) so 1/3 times 3(3a-6)=3a-6 so the equation end up as 6-a=3a-6 add 6 to both sides 12-a=3a add a to both sides 12=4a divide both sides by 4 3=a so there is one solution or A