First you had to add by twelve from both sides of equation form.
[tex]6f-12+12=-4f+6+12[/tex]
Then simplify.
[tex]6f=-4f+18[/tex]
Next, add by four-f from both sides of equation form.
[tex]6f+4f=-4f+18+4f[/tex]
Simplify.
[tex]10f=18[/tex]
Then you divide by ten from both sides of equation form.
[tex]\frac{10f}{10}= \frac{18}{10}[/tex]
Finally simplify by equation.
[tex]f=\frac{9}{5}[/tex]
Final answer: [tex]\boxed{f=9/5}[/tex]
Hope this helps!
And thank you for posting your question at here on brainly, and have a great day.
-Charlie