#### Answer

$y=-x + 4$

#### Work Step by Step

RECALL:
(1) The slope-intercept form of a line's equation is $y=mx+b$ where $m$ = slope and $b$ = y-intercept.
(2) The slope of a line is equal to $\dfrac{rise}{run}$.
Given two points on the line, rise is the increase (or decrease) in the y-value while run is the increase (or decrease) in the x-value.
The line passes through the point $(0, 4)$ therefore the y-intercept is $4$.
The line also passes through the point $(1, 3)$.
Note that from $(0, 4)$ to $(1, 3)$, there is a:
decrease in y-value of 1 unit $\longrightarrow \text{rise} = -1$
increase in x-value of 1 unit $\longrightarrow \text{run} = 1$
Thus, the slope is:
$=\dfrac{rise}{run} = \dfrac{-1}{1} = -1$
With $b=4$ and $m=-1$, the equation of the line is:
$y=mx + b
\\y = -1(x) + 4
\\y=-x + 4$