Question 983283
The attempted function being express looks like {{{y=x^2-3x-15}}}, and this does not have a slope, because a slope relies on any two points.  Slope is for a LINE.  Your function may be a parabola  (or so it seems as expressed).


Your function has a minimum.  Put into standard form and read the vertex( a minimum point) from the equation.  You also can find x-intercepts from the standard form equation.


y-intercept:
{{{x^2-2x-15=y}}}
{{{0^2-2*0-15=y}}}
{{{y=-15}}}-----------the point (0,-15)


Transform into standard form:
{{{y=x^2-2x-15}}}
{{{y=x^2-2x+1-1-15}}}
{{{y=(x-1)^2-16}}}-----------Now find the minimum point and any x-intercepts from this standard form equation.