How do you write an equation in slope-intercept form of the line through point P(-10,1) with slope -5?

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Answer 1 · 2015-05-25T21:56:08

Since we're given the slope and a point, let's start with point slope form.

The point slope form is:

$y - y_0 = m(x - x_0)$ where $m$ is the slope and $(x_0, y_0)$ is a point through which the line passes.

In our case $m=-5$ and $(x_0, y_0) = (-10, 1)$ , so we can write:

$y - 1 = -5(x - (-10)) = -5(x + 10)$

Slope intercept form is:

$y = mx+c$ where $m$ is the slope and $c$ the intercept.

To rearrange in slope intercept form, add $1$ to both sides to get:

$y = -5(x+10)+1$

$= -5x-50+1$

$= -5x - 49$

This is pretty much slope intercept form with slope $m=-5$ and intercept $c = -49$ .

If we are really picky, we might write:

$y = -5x + -49$

Answer 2 · 2015-05-25T22:09:24

The equation in slope-intercept form is $y=-5x-49$ .

Slope-intercept form: $y=mx+b$ , where $m$ is the slope and $b$ is the y-intercept.

Substitute the known values into the equation, then solve for $b$ .

$y=1$ m $=-5$
$x=-10$

$y=mx+b$ =

$1=-5(-10)+b$ =

$1=50+b$

$-49=b$

$y=-5x-49$