I would say TF - T. So, truth false thruth.
If f(x)=69-15x then 
Given :

Lets find out
. The steps to find out f inverse are
Replace f(x) by y

Now we find 
Replace inverse function in the place of x in f(x)

Learn more :
brainly.com/question/11242094
1) x+17=20
x-10=30
2) x/4=20
x/30=2
3) 4(x+5)=40
4) x+3.2=6
5) A pizza place sells pizza for $5 per box. If I had $20 how many pizzas can I buy in all? (5x=20)
Hope this helps! Have a wonderful day.