17 that’s the answer I did this one before
√(- 9 ) / (( 4 - 7 i ) - ( 6 - 6 i )) = 3 i / ( 4 - 7 i - 6 + 6 i ) =
= 3 i / ( - 2 - i ) = - 3 i / ( 2 + i ) =

=
- 1 - 2 i
Answer:
Because most kids dont like going to church.
Let p and w represent the speed of the plane and the speed of the wind, respectively.
.. speed = distance/time
.. p +w = 720/3 = 240
.. p -w = 720/4 = 180
Add the two equations to eliminate w.
.. 2p = 420
.. p = 210
.. w = p -180 = 30
The speed of the wind is 30 mph.
The speed of the plane in still air is 210 mph.