here's a nice hack
if you have [tex]y=ax^2+bx+c[/tex]
the x value of the vertex is [tex]\frac{-b}{2a}[/tex]
fo if we have
[tex]y=1x^2-4x+3[/tex]
b=-4
a=1
the x value of the vertex is
[tex]\frac{-(-4)}{2(1)}=\frac{4}{2}=2[/tex]
subsitutie that for x to find y value
[tex]y=1(2)^2-4(2)+3[/tex]
[tex]y=1(4)-8+3[/tex]
[tex]y=4-5[/tex]
y=-1
the vertex is (2,-1)
