# How do you graph y=1/4x-1 using slope intercept form?

Nov 12, 2017

A line passing through $\left(0 , - 1\right)$ and $\left(4 , 0\right)$

graph{1/4x-1 [-7.82, 12.18, -4.6, 5.4]}

#### Explanation:

We need to find two points, then join up the line. The natural points to go for are those on the x-axis and the y-axis.

To find the point where it crosse the y-axis:

Let $x = 0$
$y = \frac{1}{4} \left(0\right) - 1$
$y = - 1$
$\therefore$ crosses at $\left(0 , - 1\right)$

You can also tell this from the value of $c$ from the general equation $y = m x + c$, as, if $x = 0 , y = c$ Since $c = - 1$, it passes through $\left(0 , - 1\right)$, although I'd say its more formal to go through the algebra.

Now to find where it crosses the x-axis:

Let $y = 0$
$0 = \frac{1}{4} x - 1$
$1 = \frac{1}{4} x$
$x = 4$
$\therefore$ crosses at $\left(4 , 0\right)$

We can now join up these two points like so:

graph{1/4x-1 [-7.82, 12.18, -4.6, 5.4]}