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How to plug a value into an expression on a TI-89 Titanium

By E-Code · updated

Type the expression, press | (the with key, under ◆), type the value like x=2 and press ENTER: x^2+3x|x=2 gives 10, and x keeps no value afterwards.

Step by step

  1. Type the expression. X ^ 2 + 3 X Type x^2+3x. X has its own key, and 3x means 3 times x.
  2. Press the with key. | Press |, the key under ◆. It means "with": whatever comes after it is only true for this line.
  3. Say what x is. X = 2 Type x=2. x is not changed for good, only for this one sum.
  4. Work it out. ENTER Press ENTER. The TI-89 puts 2 in place of every x.
  5. Read the answer. 2² + 3·2 = 10. Press ▲ and ENTER to reuse the line, then change the 2 to try other values.

What the screen shows

2² + 3·2 = 10. Press ▲ and ENTER to reuse the line, then change the 2 to try other values.

Look for 10 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 “Plug a value into an expression” on the TI-89 calculator

Related

Math programs for the TI-89 Titanium:

All TI-89 hidden tricks guides · All TI-89 guides · All calculator guides