College algebra question. inequalities interval

[camilus]

Homework Statement

Solve the following inequality and express the solution set in interval notation.

http://www.webassign.net/www24/symImages/4/6/aaf987edafbf00c172f8cfaf01966c.gif

The Attempt at a Solution

I got most of the answer right, except the lower interval.

the answer is:

( ? , 4 )

the question is find the ?

it is a negative number like -4x10^8, and I have narrowed it down to somewhere around -3.98558x10^8, but whata ****, how the hell m I supposed to get EXACT number?

 

[camilus]

haha nevermind sorry guys, I got the aswer already, it was -7..