Question #b04b9

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Answer 1 · 2016-08-10T19:05:02

$y = -5x -21$

Slope intercept form means $y = mc + c$ because in this form we can read off the slope (m) and the y-intercept directly.

We know the slope, but the point $(-5.4)$ is not the y-intercept.
It would have to be $(0,c)$

There are 2 methods:

Method 1 .: Substitute into $y = mx +c$ and find a value for $c$

$4 = (-5)(-5) + c$
$4 = 25 + c$
$-21 = c$
Substitute for $m and c$

The required form is $y = -5x -21$

Method 2: Substitute into $y-y_1 = m(x-x_1)$

$y-4 = -5(xcolor(red)(-(-5)))$

$y color(blue)(-4)= -5(xcolor(red)(+5))$
$y = -5x -25color(blue)(+4)$