# How do you find the axis of symmetry, and the maximum or minimum value of the function #y = x^2 + 3x #?

##### 2 Answers

Of form that has a minimum duo to the coefficient of

Axis of symmetry is:

#### Explanation:

The

Just for a moment, suppose we had

Consider the general case of

Write this as:

The axis of symmetry is at

So in this case we have:

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Set

Axis of symmetry

Minimum value

Maximum value

#### Explanation:

To put the equation in standard form, x-terms are made into a perfect square. In the given expression consider the coefficient of x, which is 3. Half of this is

The equation in this form represents a vertical parabola, opening up, with vertex at

The axis of symmetry is

Minimum value is