Using Form - HP -28S Manual

Isolate x. The command ISOL appears in the second row of the AL-
GEBRA menu as well as the SOLVE menu.
I
NEXT
I
ISOL
The expression returned represents a symbolic solution of the equa-
tion for x-that is, the equation
2(a
+
x)
=
3(b - x)
+
c
is satisfied when x
=
(3b
+
c - 2a)j5.
Using FORM
If there are multiple occurrences of x, and if any occurrence has a
symbolic coefficient, the command COLCT won't combine the coef-
ficients. The next example isolates
x
in the equation
a(x
+
b)
+
2x
=
c,
where
x
occurs more than once and has a symbolic coefficient
a.
The
strategy is to expand the equation, use FORM to collect coefficients of
x, and then isolate x.
Put the equation on the stack.
~
A
0[0
X
eB
B
.[DeB
2
0
X
0
c
I
ENTER
I
Expand the equation.
I
NEXT
I
EXPAH
Now use FORM to collect the coefficients of x.
FORM
112 9: Symbolic Solutions