The equation below describes a parabola. If a is negative, which way does the parabola open?y=ax^2a. downb. leftc. upd. right

Given equation : y=ax^2 
Taking a to the other side we have, x^2=(1/a)*y
 This equation describes a parabola that opens up.
 When a is negative, the focus is on the negative y-axis, therefore, the parabola opens down.
 The answer is a. down.