Answer:
f=5.4
Step-by-step explanation:
2f+8.74=19.54.
what you want to do first is subtract 8.74 from both sides so your equation should look like this:
2f=10.80
Then you want to divide both sides of your equation by 2/f
so 10.80/2f=5.4
which means that f=5.4
Hope this helps! :D