Question 706871
Here is how to begin:


x=-10,
{{{(-10)^2+b(-10)+c=0}}}
{{{100-10b+c=0}}}


x=5,
{{{(5)^2+5b+c=0}}}
{{{25+5b+c-0}}}


This system is now ready to study:
100-10b+c=0
25+5b+c=0


You might want it in this form:
-10b+c=-100
5b+c=-25


Or better, like this:
{{{10b-c=100}}}
{{{5b+c=-25}}}
Solve this system for b and c.