(2/3)-5a=(-1/3)(-9a+4)

(2/3)-5a=(-1/3)(-9a+4)   multiply both sides by 3 to clear the fracrions

2 - 15a = (-1)(-9a +4)     simplify the right side

2 - 15a = 9a - 4               add 15a and 4 to both sides

6 = 24a                           divide both sides by 24

6/24 = a  =  1/4