SOLUTION: the vertex and x-intercepts y=(x-4)(x+2)

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Question 447583: the vertex and x-intercepts y=(x-4)(x+2)
Answer by MathLover1(20850) About Me  (Show Source):
You can put this solution on YOUR website!

y=%28x-4%29%28x%2B2%29
You know two points on the graph;
(4,0) and (-2,0),
for those are the x+-intercepts you stated above
Since parabolas are always symmetrical, you know that the x coordinate of the vertex must be exactly+half+way between these two coordinates(since they have the same y value), somewhere along the line x=1
plug 1 into the equation, and see what value you get for y:
y+=+%281-4%29%281%2B2%29
y+=+-3%283%29
y+=+-9
so, the vertex is at (1,-9)