# How do you identify the important parts of f(x)= 2x^2 - 11 to graph it?

Sep 23, 2015

Any quadratic equation of form $y = a {x}^{2} + b x + c$ has a parabola graph.

If a is positive (like here a = 2) then the arms go up.

In this case, c = -11 and represents the y-intercept.

The roots or x-intercepts of the equation are when y = 0, So in this case when $2 {x}^{2} - 11 = 0 \implies x = + \mathmr{and} - \sqrt{\frac{11}{2}}$

The axis of symmetry is at $x = \frac{- b}{2 a} = 0$ in this case.

Then you can combine it all to draw the graph.

graph{2x^2-11 [-25.66, 25.65, -12.83, 12.83]}