How do you find the axis of symmetry, graph and find the maximum or minimum value of the function #y=2x^2-7x-8#?

1 Answer
Mark D.
Jun 17, 2018

#x=7/4# is the axis of symmetry
#(7/4,-113/8)# is the minimum
y intercept is -8

Explanation:

It is a positive #x^2# so it will be a #uu# shaped parabola

#(-b)/(2a)# will give the x coordinate of the vertex

#7/4#

Put this into the equation to find the y coordinate

#2xx(7/4)^2-7xx7/4-8#

#98/16-49/4-8=-113/8=-12 1/8#

Construct a table of values, putting values of x into the equation to get the relevant y values in order to plot the graph.
Use values between -2 and 2 for x

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