What is the the vertex of #y=2x^2+15x -2 #?

1 Answer
Feb 28, 2016

#x_("vertex")=-3.75#

I will let you work out #y_("vertex")#

Explanation:

Tony B

Given:#" "y=2x^2+15x-2#

A quick way of finding #x_("vertex")# is as follows:

Write as #" "y=2(x^2+15/2x)-2#

Now apply :#" "(-1/2)xx15/2 = -15/4 = 3.75#

#color(blue)(x_"vertex"=-3.75)#
'~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Now substitute back into the original equation to find #y_("vertex")#