Answer:
the moment of take-off
Step-by-step explanation:
it is in-between before and after take off
In my guess I'll go for Slope = y-intercept = 10
$80
4x/2=2x
7x-60
7x-60=2x*2
7x-60=4x
3x=60
x=20
20*4=80
-2 15 ...................