# How do you write the equation in slope-intercept form of the line that has a slope of 3 and contains the point (4, 9).?

Apr 16, 2016

$y = 3 x + 3$

#### Explanation:

Slope-intercept form of a line is $y = m x + c$, where $m$ is the slope and $c$ is the y-intercept.

The question gives us $m = 3$ already, so

$y = 3 x + c$.

Now substitute in values for $x$ and $y$ from the point that has been given and rearrange to find $c$.

${9}_{y} = 3 \cdot {4}_{x} + c$
$c = 9 - 12 = - 3$

and insert this into the line equation,

$y = 3 x - 3$