#### Answer

(a)
slope =$-200$.
y-intercept: $(0, 300)$
x-intercept: $(1.5, 0)$
(b) $y=-200x+300$

#### Work Step by Step

RECALL:
(1) The slope is the ratio rise (change in y) over run (change in x).
(2) The x-intercept is the point where the graph touches/crosses the x-axis.
(3) The y-intercept is the point where the graph touches/crosses the y-axis.
(4) 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.
(a) From the point $(0, 300)$ to the point $(1, 100)$, the change in $y$ is $-200$ while the change in $x$ is $1$. Thus, the slope is $\frac{-200}{1}=-200$.
The graph crosses the y-axis at the y-intercept $(0, 300)$.
With a slope of $-200$, from $(1, 100)$, a change of $0.5$ unit in the value of $x$ gives a $-100$ unit decrease in $y$, leading to the x-intercept $(1.5, 0)$.
(b) With a slope of $-200$ and a y-intercept of $(0, 300)$, then the equation of the line is $y=-200x+300$.