HP 39g Graphing Calculator - Manual (Page 90)

Interpreting results
After Solve has returned a solution, press D3B in the Numeric
view for more information. You will see one of the following
three messages. Press HE to clear the message.
Message
Zero
Sign Reversal
Extremum
Condition
The Solve aplet found a point where
the value of the equation (or the root of
the expression) is zero within the
calculator’s 12-digit accuracy.
Solve found two points where the
value of the equation has opposite
signs, but it cannot find a point in
between where the value is zero. This
might be because either the two points
are neighbours (they differ by one in
the twelfth digit), or the equation is not
real-valued between the two points.
Solve returns the point where the value
is closer to zero. If the value of the
equation is a continuous real function,
this point is Solve’s best
approximation of an actual root.
Solve found a point where the value of
the equation approximates a local
minimum (for positive values) or
maximum (for negative values). This
point may or may not be a root. Or:
Solve stopped searching at
9.99999999999E499, the largest
number the calculator can represent.
7-6 Solve aplet