f(3)=-3(4-3)+2

Solution for f(3)=-3(4-3)+2 equation:

f (3)=-3 (4-3)+2

We simplify the equation to the form, which is simple to understand 
f(3)=-3(4-3)+2

Simplifying terms in parentheses
f*(3)=-3*(+1)+2

Reorder the terms in parentheses
+(+3f)=-3*(+1)+2

Remove unnecessary parentheses
+3f=-3+*(+1+)+2

Reorder the terms in parentheses
+3f=+(-3)+2

Remove unnecessary parentheses
+3f=-3+2

We move all terms containing f to the left and all other terms to the right. 
+3f=-3+2

We simplify left and right side of the equation. 
+3f=-1

We divide both sides of the equation by 3 to get f. 
f=-0.333333333333