How did they compute this e equation?

[myusernameis]

Homework Statement

this is a question I'm working on, and there's this step I'm stuck on
it looks like this:

Homework Equations

The Attempt at a Solution

how come the 9.8 became the 50?

thanks

 

[rock.freak667]

$$\int e^{ax}dx= \frac{1}{a}e^{ax}+C$$

 

[myusernameis]

$$\int e^{ax}dx= \frac{1}{a}e^{ax}+C$$

ohhHHHH ... it seems all simple now

thanks!