Question 830385
What is the vertex of y=(2x-3)(2x+1). I'm confused on what to do when there's a number in front of the x
<pre>y = (2x - 3)(2x + 1)
{{{y = 4x^2 - 4x - 3}}} ------ FOILing the binomials
{{{x = - b/2a}}} ------ Formula for the x-coordinate of the vertex, with:
a being + 4, and b being - 4 
{{{x = - (- 4)/2(4)}}} ------- Determining x-coordinate of vertex
x, or x-coordinate of vertex = {{{- (- 4/8)}}}, or {{{1/2}}}

{{{y = 4(1/2)^2 - 4(1/2) - 3}}} ----- Substituting {{{1/2}}} for x in quadratic equation 
{{{y = 4(1/4) - 4/2 - 3}}}
{{{y = 1 - 2 - 3}}}, or {{{y = - 4}}}
Vertex: ({{{highlight_green(1/2)}}},{{{highlight_green(- 4)}}})
You can do the check!! 

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