Answer
$y=-\frac{1}{2}x+1$
Work Step by Step
Let $(x_1,y_1)=(0,1)$ and $(x_2,y_2)=(4,-1)$
Slope
$\Rightarrow m=\frac{y_2-y_1}{x_2-x_1}$
Substitute all the values.
$\Rightarrow m=\frac{-1-1}{4-0}$
Simplify.
$\Rightarrow m=\frac{-2}{4}$
$\Rightarrow m=-\frac{1}{2}$
Because the line crosses the $y-$ axis at $(0,1),$ the $y-$intercept is $b=1$.
The slope-intercept form is
$\Rightarrow y=mx+b$
Substitute $-\frac{1}{2}$ for $m$ and $1$ for $b$.
$\Rightarrow y=-\frac{1}{2}x+1$
