X=2 because 3 minus 1 equals 2
F(x) = x + 3
y = x + 3
x = y - 3
Inverse is h(x) = x - 3
Using a calculator, you can find out that

and so that means

so your answer is
Answer:
Solution:
the boat's speed in still water: x
The speed with current: (x+3)
The speed against current: (x-3)
The equation is
3(x+3) = 4(x-3)
x = 21 mph
The distance = 3*(21+3)= 72 miles
I choose (A)
Step-by-step explanation: