Chapter 8.6, Problem 17E

To determine

To write:

Anequation of the line that passes through the given points.

Answer to Problem 17E

The equation of the line passing through the given pointswould be $y=-11$ .

Explanation of Solution

Given:

Two points on a line: $(-2,-11)\text{and }(0,-11)$

Concept used:

  $\begin{array}{l}m=\frac{y_2-y_1}{x_2-x_1},\text{where,}\\ m=\text{Slope of line,}\\ y_2-y_1=\text{Difference between two }y\text{-coordinates}\\ x_2-x_1=\text{Difference between two }x\text{-coordinates of same }y-\text{coordinates}\end{array}$

The equation of a line in point-slope form is $y-y_1=m\left(x-x_1\right)$ , where m represents slope of line and $\left(x_1,y_1\right)$ represents a point on the line.

Calculation:

First of all, we will find the slope of line passing through the given points.

Let point $(-2,-11)=(x_1,y_1)\text{and }(0,-11)=(x_2,y_2)$ . Upon substituting our given coordinates in slope formula, we will get:

  $\begin{array}{l}m=\frac{y_2-y_1}{x_2-x_1}\\ m=\frac{-11-(-11)}{0-(-2)}\\ m=\frac{-11+11}{0+2}\\ m=\frac{0}{2}\\ m=0\end{array}$

To write our equation, we will substitute the value of slope and coordinates of point $(0,-11)$ in point-slope form of equation as shown below:

  $\begin{array}{l}y-y_1=m\left(x-x_1\right)\left(\text{Point-slope form of equation}\right)\\ y-(-11)=0\left(x-0\right)\left(\text{Substituting given values}\right)\\ y+11=0\\ y+11-11=0-11\\ y=-11\end{array}$

Therefore, the equation of the line passing through the given points would be $y=-11$ .