Tuesday, August 1, 2017

Beginning Algebra With Applications, Chapter 5, 5.6, Section 5.6, Problem 28

Illustrate the solution set $2x -3 (y + 1) \geq y - (7 - x)$

$
\begin{equation}
\begin{aligned}
2x - 3y - 3 &\geq y - 7 + x
&& \text{Solve the inequality for } y \\
\\
-3y - y &\geq -2x + x + 3 - 7
&& \text{Group terms}\\
\\
-4y &\geq -x - 4
&& \text{Evaluate}\\
\\
\frac{-4y}{-4} &\leq \frac{-x}{-4} - \frac{4}{-4}
&& \text{Remember that if you divide or multiply negative numbers ,the inequality symbol reverses}\\
\\
y &\leq \frac{x}{4} + 1
&& \text{Simplify}
\end{aligned}
\end{equation}
$


To graph the inequality, we first find the intercepts of the line $\displaystyle y = \frac{x}{4} + 1$.
In this case, the $x$-intercept (set $y = 0$) is $(-4,0)$

$
\begin{equation}
\begin{aligned}
0 &= \frac{x}{4} + 1 \\
\\
\frac{x}{4} &=- 1\\
\\
x &= -4
\end{aligned}
\end{equation}
$


And, the $y$-intercept (set $x = 0$) is $(0,1)$

$
\begin{equation}
\begin{aligned}
y &= \frac{0}{4} + 1 \\
\\
y &= 1
\end{aligned}
\end{equation}
$


So, the graph is



Graph $\displaystyle y = \frac{x}{4} + 1 $ as a solid line. Shade the lower half-plane.

No comments:

Post a Comment

Summarize the major research findings of "Toward an experimental ecology of human development."

Based on findings of prior research, the author, Bronfenbrenner proposes that methods for natural observation research have been applied in ...