Which of the following are the coordinates of the vertex of y=x^2 - 10x+ 2?
(-5,23)
(-10,2)
(5, 23)
(2, -10)

We have 2 situation one with wind and one against wind

Speed = x , W= Wind

*case 1       ( With Wind)                     *case 2      ( Against Wind)

t=3 hr  d= 2160 m.  Rate = x + W            t=4 hr  d= 2160 m.  Rate = x - W

Distance = Rate * Time

2160 =  (x+W) * 3                                                      2160 = (x-W) * 4

2160 / 3 = (x+W)                                                        2160/4 = x-W

720 = x+W                                                                  540 = x-W

NOW 2 equations solve by substitution or elimination.  ( i did Elimination)

720 = x+W

540 = x-W

1260 = 2x    (W was eliminated) solve for x

x = 630  Speed of the Airplane 

now solve for W. W = 90  Speed of the Wind

 hope this helps