HP 35s User Manual page 331

f (x)
a
Example: A Relative Minimum.
Calculate the root of this parabolic equation:
It has a minimum at x = 3.
Enter the equation as an expression:
Keys:

X
X

x
f (x)
Case Where No Root Is Found
2
x – 6x + 13 = 0.
Display:

f (x)
x
c
Selects Equation mode.
Enters the equation.
More about Solving
b
Description:
x
D-9