Answer:

Step-by-step explanation:
If a parabola has its vertex on the y-axis, then its equation is

This parabola passes through the point R(3,9), then

The area of the right triangle PQR is

Find PQ and QR, if 

Now,

We get two possible points
and 
For point 

So,

For point 

So,

<span>use an expression
s = speed of the slower car
then
(s+20) = speed of the faster car
When they meet is after 400 miles
Write distance equation
slow car d + fast car d = 400 mi
4s + 4(s+20) = 400
8s + 80 = 400
8s = 400 - 80
8s = 320
s = 40 m/H</span>
Answer:
B: 1/5
Step-by-step explanation:
If the lines are perpendicular, they have negative reciprocal slopes
s has a slope of -5
t must have a slope of - (1/ -5)
= 1/5
Answer:
13.008 or 13 1/125 or 1626/125
Step-by-step explanation: