Question 1136663
it appears tha this will give you real roots.
in fact, it appears that one of the roots will be plus or minus c/a and the other root will be -1.


here's my worksheet that derives what i think is the answer.


<img src = "http://theo.x10hosting.com/2019/031405.JPG" alt="$$$" >


apparently one of the roots will be -c/a and the other root will be -1.


i tested this out with various value of b = c + a to see if that was true.


as far as i can tell, it is.


i chose to test this against a quadratic solver.


i chose the following scenarios.


<pre>
a     b     c       root 1     root 2
-5    -25   -20     -4         -1
-5    +15   +20     -1         +4
+5    -15   -20     -1         +4
+5    +25   +20     -4         -1
</pre>


in all of these scenarios, b = a + c.


one of the roots was -c/a and the other root was -1, as i had derived in the worksheet, confirming that the derivation was correct.


here's the results from the quadratic solver.


<img src = "http://theo.x10hosting.com/2019/031411.JPG" alt="$$$" >


<img src = "http://theo.x10hosting.com/2019/031412.JPG" alt="$$$" >


<img src = "http://theo.x10hosting.com/2019/031413.JPG" alt="$$$" >


<img src = "http://theo.x10hosting.com/2019/031414.JPG" alt="$$$" >


your solution is selection (a) real root