posted by Sabrina .
Find the coordinates of the vertex and determine whether the graph opens up or down. y=-x^2+x-5
it opens up, because the (x^2) is positive. if it was negative, it would open down. The vertex is as follows:
to find the value of vertex, solve first for when x=o, then when y=0
Actually, note that
so it opens downward
y = -(x^2 - x + 1/4) - 5 + 1/4
= -(x - 1/2)^2 - 19/4
Now it should be clear where the vertex lies.