Isolating A Variable - HP -28S Manual

Now make sl a negative sign.
-1
Return the second solution to level
1"'1
1
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1.
Ir~;a
! I
DDWElc:::::Jc:::::Jc:::::Jc:::::J
The two roots of
x
2 -
6x
+
8 are
x
4 and
x
2.
Isolating a Variable
The HP-28S can isolate a single occurrence of a variable in an equa-
tion, returning an expression representing the symbolic solution of
the equation. In other words, if
x
is the variable for which the equa-
tion is solved, and a, b, and c are the other variables in the equation,
isolating
x
produces an expression in
a, b,
and c such that the equa-
tion is satisfied when
x
has the value of the expression.
For the first example, isolate
x
in the equation
a(x
+
3) -
b
=
c.
This example is simple because there is only one occurrence of x. Later
examples show how to manipulate the equation to produce a single
occurrence of x.
Clear the stack .
• 1
CLEAR
1
Put the equation on the stack.
c:J
A
0 CD
X
G
3
.OJ
G
B
0 c
1
ENTER
1
3:
2:
1: 'A*(X+3)-B=C'
DDWElc:::::Jc:::::Jc:::::Jc:::::J
9: Symbolic Solutions 109