x2
x
=0
-2x2-11x
-2x2-11x-15=0
-2x2-11x-14=0
-2x2-11x-12=0
-2x2-11x-9=0
-2x2-11x-5=0
-2x2-11x+6=0
-2x2-11x+13=0
-2x2-11x+21=0
-15
-14
-12
-9
-5
6
13
21