Using the TI 82 to solve equations for X variable:
This procedure can be used to solve equations where Y is assumed to equal zero.
Turn on calculator by pressing the “ON” key.
Press the “Y=” key.
If the “Y1=” line contains an equation, delete it by pressing the “CLEAR” key.
In the “Y1=” line, input the equation X^4 + 3X^3 + 2X + 9 by using the
“X, T, ”, “^”, and proper numerical keys.
5. Exit the “Y=” menu by pressing the “2nd” key followed by the “MODE” key.
This executes the secondary “QUIT” function.
6. Press the “MATH” key; scroll down by repeatedly pressing the “▼” key and
select the last option (number 0), “solve”; press the “ENTER” key. You have
selected the solver function.
7. Select the “Y1=” equation that was entered by pressing the “2nd” key followed by
the “VARS” key—this executes the secondary “Y-VARS” function. Press the
“ENTER” key to select the first option (number 1), “Function…”; Press the
“ENTER” key to select the first option (number 1), “Y1”. This tells the solver
function that you want to solve the “Y1” equation.
8. Press the “,” key and then press the “X, T, ”. This tells the solver function that
you want to solve the “Y1” equation for the “X” variable.
9. Press the “,” key and then enter a numerical guess for the value of “X”. This
gives the solver function a starting point but you can just enter the number one—it
really doesn’t matter in most cases.
10. Press the “)” key. This completes the commands for the solver function to follow.
11. Press the “ENTER” key to activate the solver function.
12. The calculator should display the number: -1.607585111.*
1.
2.
3.
4.
* if there are multiple solutions for the equation when Y is equal to zero then you can
obtain the various solutions by inputting different guesses into the solver function
(step 9).