Answer:
2nd option
Step-by-step explanation:
given an exponential function in the form y = a
to find a and b use the coordinate points it passes through
using (0, 4 ) , then
4 = a [ = 1 ] , that is
a = 4 , so
y = 4
using (2, 100 )
100 = 4b² ( divide both sides by 4 )
25 = b² ( take the square root of both sides )
= b , that is
b = 5
then exponential function is
y = 4 .
Given:
The equation is
To find:
The value of b.
Solution:
We have,
Subtracting both sides by , we get
Therefore, the value of b is .
Answer:
the answer to the question is 39
Let the speed of the first train be v mph. Then the speed of the second train is:
(v + 50) mph.
Distance traveled by the first train from 3pm to 7pm = 4v miles.
The second train travels 4v miles in 2 hours (from 5pm to 7pm). Therefore the speed of the second train = (4v)/2 = 2v.
However the speed of the second train is also given by (v + 50) mph.
v + 50 = 2v
v = 50.
The speed of the first train is 50 mph and the speed of the second train is 100 mph.