Let us look at the following example.
Solve #2x^2+5x-3=0# for #x#.
(Be sure to move all terms to the left-hand side so that you have zero on the right-hand side.)
Step 1: Go to "Y=" and type in the quadratic function.
Step 2: Go to "WINDOW" to set an appropriate window size.
Step 3: Go to "CALC", and choose "zero".
Step 4: It will say "Left Bound?", so move the cursor to the left of the zero and press "ENTER".
Step 5: It will say "Right Bound?", so move the cursor to the right of the zero and press "ENTER".
Step 6: It will say "Guess?", then move the cursor as close to the zero as possible and press "ENTER".
Step 7: The zero (#X=-3#) is displayed at the bottom of the screen.
Step 8: Repeat Step 3-7 to find the other zero (#X=0.5#).
I hope that this was helpful.