16. Find the approximate values of the roots of the function $y=0.3 x^{3}-2 x^{2}-0.2 x+0.5$ by plotting its graph on the interval $[-1 ; 3]$.
Solution. The roots of the function, i.e., the values of the argument that make it zero, can be found as the abscissas of the points of intersection of the function's graph with the x-axis, since at these points $y=0$.

By creating a table of numerical values of the variables $x$ and $y$, we will plot the graph of the given function (Fig. 10). From the drawing, we find the approximate values of the roots.

![](https://cdn.mathpix.com/cropped/2024_05_22_8a069bcd8684ea7ea3dbg-019.jpg?height=377&width=303&top_left_y=224&top_left_x=883)

Fig. 10 of the function: $x_{1} \approx -0.4 ; x_{2} \approx 0.5 ; x_{3} \approx 2.6$.