How to solve an equation exactly on a TI-89 Titanium

By E-Code · updated 2026-09-27

Press F2 (Algebra) and 1 for solve(, type the equation, a comma and the variable, then ) and ENTER: solve(x^2-2=0,x) gives x = √(2) or x = -√(2).

Step by step

1. Open the Algebra menu. F2 Press F2. On the home screen, F2 is the Algebra menu.
2. Pick solve(. 1 Press 1 for solve(. It is pasted onto the entry line.
3. Type the equation. X ^ 2 − 2 = 0 , X ) Type x^2-2=0, then a comma, x and ). The x after the comma says which letter to solve for. X has its own key.
4. Solve it. ENTER Press ENTER. The TI-89 solves it with algebra, not by guessing.
5. Read both answers. x = √(2) or x = -√(2): both exact answers. Press ◆ ENTER instead if you want decimals.

What the screen shows

x = √(2) or x = -√(2): both exact answers. Press ◆ ENTER instead if you want decimals.

Look for √ on the screen.

Try it with the keys lit up

This guide is one of E-Code's Learn lessons. Open it on E-Code's TI-89 calculator and each key lights up in turn as you press it.

Try “Solve an equation exactly” on the TI-89 calculator

Related

• Factor and expand expressions
• Solve a system of equations
• Find complex roots
• Add fractions into one with a common denominator
• Split a fraction into partial fractions

Math programs for the TI-89 Titanium:

• Quadratic roots, exact when possible
• Linear system, exact answers
• Fraction calculator: exact, mixed, decimal

All TI-89 algebra guides · All TI-89 guides · All calculator guides