HP 35s Scientific Calculator - Manual (Page 273)

Miscellaneous Programs and Equations 17-3
The order in which you're prompted for values depends upon the variable you're
solving for.
SOLVE instructions:
1. If your first TVM calculation is to solve for interest rate, I, press 
I .
2. Press  . If necessary, press × or Ø to scroll through the equation list
until you come to the TVM equation.
3. Do one of the following five operations:
a. Press N to calculate the number of compounding periods.
b. Press I to calculate periodic interest.
For monthly payments, the result returned for I is the monthly interest rate,
i; press 12
 to see the annual interest rate.
c. Press B to calculate initial balance of a loan or savings
account.
d. Press P to calculate periodic payment.
e. Press F to calculate future value or balance of a loan.
4. Key in the values of the four known variables as they are prompted for; press
 after each value.
5. When you press the last  , the value of the unknown variable is calculated
and displayed.
6. To calculate a new variable, or recalculate the same variable using different
data, go back to step 2.
SOLVE works effectively in this application without initial guesses.