Answer
$a.\qquad y=-3x$
$b.\qquad\left\{\begin{array}{ll}
m=-3, & \text{slope}\\
b=0 & \text{y-intercept}
\end{array}\right.$
$c. \qquad $Graph:
Work Step by Step
$(a)$
The slope-intercept form is $\ \ y=mx+b.$
( m= slope, b= y-intercept)
Solve for y: $\left[\begin{array}{l}
2x+y=0\\
y=-3x\\
\end{array}\right]$
$(b)$
$y=-3x+0\ \Rightarrow \ \left\{\begin{array}{ll}
m=-3, & \text{slope}\\
b=0 & \text{y-intercept}
\end{array}\right.$
$(c)$
Graphing, we have a starting point,$ (0,0)$, since b=0.
Now, the slope
$m=\displaystyle \frac{\text{change in y}}{\text{change in x}}=-3=\frac{-3}{1} $, which we use like this:
Increasing x by 1 (from x=0 to x=1),
y decreases by $3$ units (from y=0 to y=$-3$).
The line passes through $(1,-3).$
Two points define the line. Draw it.
