Let's create a table, and use arbitrary values of x between -3 and 3 (if the solution is not in this interval, we can use another one later). If we call:
We want to find the x's for with f(x) = 0
This is the table:
And now we can evaluate f(x) in each value of x to complete the table:
The table is:
If we use this values and plot them in the cartesian plane.
We get:
And now if we plot a line that connects the points, we get the graph of the quadratic equation:
Since the problem ask us to find the value of x for which f(x) = 0, we can see both in the table and in the graph that this value is x = 2
