a^2/a^2-4 /3a-a^2/a^2-5a+6

$$\\a^2/a^2\;\;-4 /3*a\;\;-a^2/a^2\;\;-5a+6\\\\
=1\;\;-4/3*a\;\;-1\;\;-5a+6\\\\
=-4/3*a\;\;-5a+6\\\\
=-(4a)/3\;\;-5a+6\\\\
=-(4a)/3\;\;-(15a)/3\;\;+6\\\\
=-(19a)/3\;\;+6\\\\
=6-\frac{19a}{3}$$

I am going to give you 3 points for your good effort unknown.  

a to the 2 divided by a to the second cancels out

-4/3a-a^2/a^2-5a+6

a^2- 5a= a*a-a*a*a*a*a=-3a

-4/3a-a^2/3a+6

3a-a^2= a*a*a-a*a=1a or a

-4/a/3a+6

-4+6=2

2/a/3a

i think thats as far as i can get