GNU Emacs Calc 2.02 Manual
3.7.49 Algebra Tutorial Exercise 2
Suppose our roots are [a, b, c]. We want a polynomial which
is zero when x is any of these values. The trivial polynomial
xa is zero when x=a, so the product (xa)(xb)(xc)
will do the job. We can use a c x to write this in a more
familiar form.
 1: 34 x  24 x^3 1: [1.19023, 1.19023, 0]
. .
r 2 a P x RET

 1: [x  1.19023, x + 1.19023, x] 1: (x  1.19023) (x + 1.19023) x
. .
V M ' x$ RET V R *

 1: x^3  1.41666 x 1: 34 x  24 x^3
. .
a c x RET 24 n * a x

Sure enough, our answer (multiplied by a suitable constant) is the
same as the original polynomial.