How do you write the equation for the line that passes through point (4, -5) with a slope of 4?

Oct 10, 2015

$y = 4 x - 21$

Explanation:

$y = k x + n$, $k$ is slope $\implies k = 4$

$A \left(4 , - 5\right) \implies x = 4 , y = - 5$

Inserting data into $y = k x + n$ gives us:

$- 5 = 4 \cdot 4 + n \iff n = - 5 - 16 \iff n = - 21$

And hence:

$y = 4 x - 21$