Question

Please can anybody help me with this thanks i suck at this type thanks

starting from 100 ft away. your friend skates toward you and then passes you. she skates at a constant speed of 20ft/s. her distance d from you in feet after t seconds is given by d=/100-20t/. at what times is she 60 ft from you?

Answer 1

easy

d=60
60=|100-20t|

assume
if a=|b|
then
-a=b and a=b

s
60=100-20t and -60=100-20t
solve each
add 20t to both sides

60+20t=100 and 20t-60=100
minus 60 to both sideso n first, and add 60 to both sides on second
20t=40 and 20t=160
divide both sides by 20
t=2 and t=8


at t=2 and 8

Answer 2

The equation is already formulated for you which is

d = 100-20t

All you have to do is replace d with 60 ft, then you can solve for t which is asked.

60 = 100 - 20t
20t = 100 - 60
20t = 40
t = 40/20
t = 2 s

Therefore, she is 60 ft from you after 2 seconds.