# How can I tell whether a horizontal parabola opens to the left or the right?

##### 1 Answer

The same way you tell if a parabola opens up or down, by the leading coefficient of the variable.

Since the **(3)** means it opens to the right. eg.

#y=+-sqrt(3x-4)+3#

And a negative leading coefficient **(-2)** means it opens to the left.

#y=+-sqrt(4-2x)+2#

Note that only the top halves of the parabolas are drawn.