Fistly show that: 93x+1=3y
To find x we need to get the left hand side of the equation to be 3m(3x+1) where 3m=9.
I know that 32=9 (but if you don't you can use m=log3(9)=2)
This gets us: 32(3x+1)=3y
Therefore: 2(3x+1)=y
Finally y=6x+2 so a=6 and b=2