Question 210380
You have the correct x intercepts. Now you need to find the minimum point. You can see by looking at the function that the value {{{x=0}}} will cause f(x) to be as small as it can get.
So calculate f(0)
{{{f(0) = 7*0^2 - 2}}} = {{{-2}}}
Plot the points (0, -2), (0.534, 0) and (-0.534, 0)
Now draw a nice parabola thru them. If you need more points, just pick some x values (like 1 and -1), evaluate f(x) at those values for x and then plot those points too
{{{graph(400,400, -5,5,-10,10, 7x^2-2)}}}