# How do you find the vertex and intercepts for #y = x^2 - 4x#?

##### 2 Answers

See below.

#### Explanation:

Quick answer:

Solve

When

**Vertex:** is midway between the intercepts. The midpoint is the average.

When

The vertex is

A different method that uses

#### Explanation:

Given:

Write as

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

Note that in the standardised form of

By substitution

Vertex

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

The

Factorising

The common term is

The x-intercepts are at

Thus