This equation represents the multiplication of two binomials.
The inputs to this equation are:
If you input the coefficients of the x terms of each binomial and the constants of each binomial into the equation, along with any value for x, this equation computes the resultant value.
So, for example as the video shows, if you input:
x1= 1 and c1 = 4 for the first binomial and x2 = 1 and c2 = 3 for the second binomial
the binomial product evaluates to x2 + 7x + 12.
You input a value for x, let's say the value x = 2 just as an example and the equation outputs: 22 + (7 x 2) + 12 = 30.
Try it yourself. The defaults for this equation are the value for the example above but you can change any of the inputs to try the binomial multiplication on your own input values.
Here is a visual depiction of the process of multiplying the two binomials in our example above. This video came from