College Algebra & Trigonometry, 2018a

2.2. SOLUTION BY GRAPHING 93
Then we graph the function and look for which x values will make the y value
equal to 0.
6
y = x 3 − 3x 2 − 2x +7
4
2
−1 1 2 3
−2
−4
In this graph, we can see three roots, or x-intercepts, where the graph crosses the
x-axis. These are the x-values that make the y-value equal to 0. We can use the
available technology to find these x-values.
6
y = x 3 − 3x 2 − 2x +7
4
2
x ≈−1.491
x ≈ 2.834
−1 1 2 3
x ≈ 1.657
−2
−4
So, we can see that the solutions to the eqaution x 3 − 3x 2 − 2x +7=0are
x ≈−1.491, 1.657, 2.834.
We can check these answers by plugging them back into the original equation.