For this case, the first thing we must do is define variables:
p: plane speed
w: wind speed
With the wind in favor, the speed is:

With the wind against the speed is:

Rewriting both equations, we have the following system of equations:

Then, solving the system of equations (graphically for example), we have the solution is:

Therefore, jet stream's speed:
Answer:
A) p + w = 960; p - w = 600; jet stream's speed = 180 km / h
12x - 18 - 4x -2
12x - 4x = 8x (yours 12x - 4x = 8)
-18 - 2 = -20 (yours -18 -1 = 17)
answer:
8x - 20
There should be 6 per number
ex.
1234
1243
1342
1324
1432
1423
Domain={-4,3} range={2,3}
Answer:34.333 repeating
Step-by-step explanation: