HP 39gs Master Manual page 204

POLYROOT([coeff1,coeff2,...])
This function returns the roots of the polynomial whose coefficients are
specified. The coefficients must be input as a vector in square brackets.
Eg. Using our earlier function of f x
[1, 0, -7, 6].
As you can see in the screen shot, the roots of 2, -3 and 1 have been correctly found.
See page 309 for details on finding roots of real and complex polynomials using the CAS on the hp 40gs.
( ) = (x − 2)(x + 3)(x −1) = x
204
− 7x + 6 we can enter the coefficients as
3