# How do you graph y = -x^2 + 3?

Sep 23, 2015

Refer Explanation section.

#### Explanation:

It has no $x$ term in it. You supply -

$y = - {x}^{2} + 0 x + 3$

vertex formula $\frac{- b}{2 a}$
Find the vertex
$x = \frac{- b}{2 a} = \frac{0}{2 \times 1} = 0$
Its vertex is at $x = 0$
Find a few numbers on either side of zero.
Find their $y$ values.
Plot the pairs on a graph sheet.
Join them with a smooth curve.

x: y
-3: -6
-2: -1
-1: 2
0: 3
1: 2
2: -1
3: -6

graph{-x^2 +3 [-10, 10, -5, 5]}