2/3(-9m+12)

(Expand this out)

= (-9m*2)/3 + (12*2)/3

(Simplify this down)

= -6m + 8

$$\\\frac{2}{3}\times (-9m+12)\\\\ =\frac{2}{\not{3}}\times \not{3}(-3m+4)\\\\ =2(-3m+4)\\\\ =-6m+8$$