Question

The equation y=ax^2 describes a parabola. If the value of a is positive, which way does the parabola open?

A.Up
B.Right
C.Left
D.Down

Answer 1

A. Up

Explanation:

Parabolas are graphs that make U-shapes and are formed from quadratic equations.

Vertical Parabolas

There are 2 different types of parabolas: vertical and horizontal.

• Vertical parabolas have a vertical axis of symmetry. So, they open up or down.
• Horizontal parabolas have a horizontal axis of symmetry. So, they open left or right.

If the x-value is squared, then the parabola is vertical. So, this graph must open up or down.

Positive A-Value

The a-value is the coefficient before the squared term. In a vertical parabola, the graph opens up if the a-value is positive. On the other hand, the graph opens down when the a-value is negative.

In this case, the graph is a vertical parabola that opens up. This means that the range will have a minimum value but no maximum.