Answer:x-12
Step-by-step explanation:
Area=x^2-8x-48
Width=x+4
length=area/width
length=(x^2-8x-48)/(x+4)
length=((x+4)(x-12))/(x+4)
length=x-12
What the dude above you said
Let the time be x
Then the first train will go 70x mi
other train will go 80x mi
As the are passing through opposite direction.
then
70x+80x = 600
or, x = 4
