Example 4 – HP 40gs User Manual
Page 279
Step-by-Step Examples
16-5
Press
to select the entire
equation, then press
to reduce it to
.
Press ,
select
FACTOR, press
and
then
. The result is
as shown at the right.
Now press
, select
SOLVEVX, press
and
press
. The result is
shown at the right.
Press
to display
CAS history, select D or a
version of it, and press
.
Press ,
select
SUBST,
press
and, then
complete the second
argument:
Press
to
select
the entire expression and
then
to obtain the
intermediate result shown.
Press
once more to
yield the result:
.
Therefore,
when
.
Example 4
A baker produces two assortments of biscuits and
macaroons. A packet of the first assortment contains 17
biscuits and 20 macaroons. A packet of the second
assortment contains 10 biscuits and 25 macaroons. Both
packets cost 90 cents.
Calculate the price of one biscuit, and the price of one
macaroon.
Solution: Let x be the price of one biscuit, and y the
price of one macaroon. The problem is to solve:
9x
2
6x
–
80
–
x
5
–
=
175
D
175
=
x
5
–
=
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