Question 1142378
.
<pre>
Since the coefficient at x^2 is negative (its value is -2), the graph opens downwards.


The x- coordinate of the vertex is  x= {{{-b/(2a)}}} (referring to the standard form of the quadratic function y = ax^2 + bx + c,

in which  a= -2, b= 9).


Thus the x- coordinate of the vertex is  x= {{{-9/(2*(-2))}}} = {{{9/4}}} = {{{2}}}{{{1/4}}}  in this case.


Among the given 5 optional answers, only n1 satisfies these conditions -- so, only n1 is the potential candidate.


Now substitute  x= {{{2}}}{{{1/4}}}   into the formula of the parabola to verify that y  then equals  {{{15}}}{{{1/8}}}.


Do this last check on your own.
</pre>

I completed my instructions.