Enter the number you want to set first, then press SHIFT, then press RCL, then press the letter you want to set, and you will see the page {2→A 2}, and then enter b c in turn.
Use the formula (-b √ B2-4ac) ÷ 2.
To have (-b √ B2-4ac) ÷ 2, you follow me (you have to set ABC first).
1 RCL (-) means RCL) means X X2+. ,, that is, b) that is, X+hyp that is, C = ok.
Don't understand?