Chapter 9.3, Problem 27PPS

To determine

To solve the given equation using graphing.

Answer to Problem 27PPS

The values of x are -6 and 3 .

Explanation of Solution

Given information :

The function provided is $x^2+3x=18$ . This can be written as $x^2+3x-18=0$

Formula used :

The given equation would be graphed as a function and the points of x-intercepts would be the results. For these points, the x-coordinate shall serve the purpose of the results.

To cross check, put these values in the given equation to confirm that the left-hand side and right-hand side matches.

Calculation :

The graph of the given equation is

In this, the parabola x-intercepts at $\left(-6,0\right)$ and $\left(3,0\right)$ .

Now, cross check by putting these values of x-coordinate in the given equation.

  $x^2+3x-18=0$

This is the given equation.

  $=>{\left(-6\right)}^2+3\left(-6\right)-18=0$

Putting $x=-6$

  $=>36-18-18=0$

Simplifying this

  $=>0=0$

Now, put the other result.

  $=>{\left(3\right)}^2+3\left(3\right)-18=0$

Putting $x=3$

  $=>9+9-18=0$

Simplifying this

  $=>0=0$

Thus the test is a success and the result is -6 and 3 .