What is the vertex form of #y= (x+2)(x - 7) #?

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Answer 1 · 2017-06-14T09:00:36

minimum vertex #-81/4# at #(5/2, -81/4)#

#y = (x + 2)(x - 7) = x^2 - 5 x - 14#

use completing a square to solve
#y = x^2 - 5 x - 14#

#y = (x -5/2)^2 -(-5/2)^2 - 14#

#y = (x -5/2)^2 - 25/4 - 56/4#

#y = (x -5/2)^2 -81/4#

since #(x -5/2)^2# is +ve value, therefore it has a minimum vertex #-81/4# at #(5/2, -81/4)#