#### Answer

$\color{blue}{y=-2x+5}$

#### Work Step by Step

RECALL:
The slope-intercept form of a line's equation is $y=mx+b$ where $m$=slope and $(0, b)$ is the line's y-intercept.
The given line has a slope of $-2$ therefore the tentative equation of the line is $y=-2x+b$.
To find the value of $b$, substitute the x and y values of the given point into th tentative equation above to obtain:
$y=-2x+b
\\3=-2(1)+b
\\3=-2+b
\\3+2=-2+b+2
\\5=b$
Therefore, the equation of the line is $\color{blue}{y=-2x+5}$.