
converges by the ratio test for

The limit is 1, so the series converges as long as

which indicates a radius of convergence of 3.
Answer: Luis started by adding 4.8b to both sides
Step-by-step explanation:
4.8 is a positive number so therefore it should be subtracted from both sides to make the right side be empty in that position.
Let
x--------> the time in hours
y-------> the distance in miles
we know that
The speed is equal to

in this problem


<u>Equation First Train</u>

<u>Equation Second Train</u>

---------> equation 
Substitute the values of
and
in the equation 

Solve for x


therefore
<u>the answer is</u>

The sum of the squared legs must give the squared hypotenuse:

But of course we can only accept the positive solution, because
is a length and can't be negative.