Chapter 8.7, Problem 37HP

To determine

To write a real-world problem that can be represented by an equation in the form $y=mx+c$ and solve by graphing

Answer to Problem 37HP

Aline that has y-intercept but no x-intercept is parallel to x-axis. Slope of line parallel to x-axis is zero.

Explanation of Solution

Given information: Areal-world problem that can be represented by an equation in the form $y=mx+c$ line that has a y-intercept but no x-intercept

Formula Used:

Slope intercept form of equation of line is

  $y=mx+c$

Where

  $m=$ Slope of line

  $c=$ y-intercept

Calculation:

A real-world problem that can be represented by an equation in the form $y=mx+c$

A company offers a plan where they charge $\$15$ per month and $\$0.25$ for each call made or received

Let the number of calls made or received in a month be $x$

Equation is given as

  $y=15+0.25x$

Finding the solution of the equation:

When $x=0$

  $\begin{array}{l}y=15+0.25\left(0\right)\\ y=15+0\\ y=15\end{array}$

When $x=10$

  $\begin{array}{l}y=15+0.25\left(10\right)\\ y=15+2.5\\ y=17.5\end{array}$

Thus, solutions are $\left(0,15\right)$ and $\left(10,17.5\right)$

Plotting the points to graph the equation:

  

Conclusion:

Hence, a line that has y-intercept but no x-intercept is parallel to x-axis. Slope of line parallel to x-axis is zero.