How do you find the equation of a line with slope of -3 and contains the point (0, -3)?

Dec 8, 2017

$y = - 3 x - 3$

Explanation:

Formula for a line: $y = a x + b$
$a$ represents slope which is $- 3$
$y = - 3 x + b$
Then we know this line must go through the point (0,-3).
So x=0 and y=-3. Let's substitute and find the value of $b$

$- 3 = - 3 \cdot 0 + b$
$- 3 = b$
and finally we have everything we need: $y = - 3 x - 3$