How many solutions does the equation have? 6-a = 1/3(9a-18)
a. one solution
b. infinite solutions
c. no solution

6 - a =  (9a - 18)

First, simplify  to  / Your problem should look like: 
Second, multiply both sides by 3. / Your problem should look like: 
Third, expand. / Your problem should look like: 
Fourth, add 3a to both sides. / Your problem should look like: 
Fifth, simplify 9a - 18 + 3a to 12a - 18. / Your problem should look like: 
Sixth, add 18 to both sides. / Your problem should look like: 
Seventh, add 18 + 18 to get 36. / Your problem should look like: 
Eighth, divide both sides by 12. / Your problem should look like: 
Ninth, since 3 goes into 12 to get 36, simplify  to 3. / Your problem should look like: 
Tenth, switch sides. / Your problem should look like: 

 a = 3 (one solution)