Texas Instruments TI-89 Manuale Utente
Previews
83
equation, and solve for the value of y. Then substitute the y value back into the first
equation to solve for the value of x.
equation to solve for the value of x.
Steps and keystrokes
Display
1. Display the Home screen and clear the
entry line. Solve the equation 2x N 3y = 4
for x.
„
for x.
„
1
selects
solve(
from the Algebra
menu. You can also type
solve(
directly
from the keyboard or select it from the
Catalog
.
Press "
M M „ 1 2 X | 3 Y
Á 4 b X d ¸
2. Begin to solve the equation Lx + 7y = L12
for y, but do not press
¸ yet.
Press
„ 1 ? X « 7 Y Á ? 12 b Y d
3. Use the “with” operator to substitute the
expression for x that was calculated from
the first equation. This gives the value of
y.
the first equation. This gives the value of
y.
The “with” operator is displayed as | on
the screen.
the screen.
Use the auto-paste feature to highlight the
last answer in the history area and paste
it to the entry line.
last answer in the history area and paste
it to the entry line.
Press Í
C ¸ ¸