The directrix of the parabola -40x= y2 is:
y=-10
x= 10
x=-10
y= 10

Me find the measure to side c and the process to solve the problem you appreciate it : )

Write an equation in point-slope form for the line through the given point that has the given slope (-2,-7); m=-3/2

Two planes leave an airport at the same time, one flying east, the other flying west. the eastbound plane travels 20 mph slower. they are 1600 mi apart after 2 hr. find the speed of each plane.