x2
x
=0
-10x2+21x
-10x2+21x-11=0
-10x2+21x-9=0
-10x2+21x-8=0
-10x2+21x-2=0
-10x2+21x+10=0
-10x2+21x+13=0
-11
-9
-8
-2
10
13