We have:

Then we use trigonometric identities to change the negative sign of the trigonometric functions, so:

We clear f(x):

we simply what we can:

Thus, the correct answer is;
<span>going downstream -
t = 14/(2 + v)
going upstream -
t = 7/(2 - v)
14/(2 + v) = 7/(2 - v)
(2 + v)/2 = 2 - v
v = 2/3km/h</span><span>
</span>
Answer:
2 i think
Step-by-step explanation:
Isn’t that suppose to be with graphs?