Beginning Algebra With Applications, Chapter 5, 5.3, Section 5.3, Problem 58
Graph $\displaystyle x-3y = 6$ by using the slope and $y$-intercept.
$y$-intercept:
$
\begin{equation}
\begin{aligned}
x-3y =& 6
&& \text{Given equation}
\\
0-3y =& 6
&& \text{To find the $y$-intercept, let } x = 0
\\
-3y =& 6
&& \text{Simplify}
\\
y =& -2
&&
\end{aligned}
\end{equation}
$
The $y$-intercept is $(0,-2)$
Writing the equation in slope form, $y = mx+b$
$
\begin{equation}
\begin{aligned}
-3y =& 6-x
\\
\\
y =& \frac{6-x}{-3}
\\
\\
y =& \frac{1}{3}x- 2
\end{aligned}
\end{equation}
$
$
\begin{equation}
\begin{aligned}
m =& \frac{\text{change in } y}{\text{change in } x}
\\
\\
m =& \frac{1}{3}
\end{aligned}
\end{equation}
$
Beginning at the $y$-intercept, move to the right 3 units and then up 1 unit.
$(3, -1)$ are the coordinates of a second point on the graph.
Draw a line through $(0,-2)$ and $(3, -1)$
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