How do you calculate crossover point on BA II Plus calculator ?

SOURCE: No decimal display on TI BA-II calculator

Your BA II PLUS stores numeric values internally to an accuracy of 13 digits. However, the numbers it displays depends on the number of decimal places to which you have it set (choice of 0–9 or floating decimal). To set the number of decimal places displayed to three: hit [2ND][FORMAT][3][ENTER]This setting also continues indefinitely (even though the calculator is turned off and on) until it is changed.

SOURCE: BA-II Plus payment problem

I just took the battery out and it reset itself.

SOURCE: is it possible to calculate cube root or higher

To extract the roots of orders higher than 2, you can use the universal power key labeled as [Y to x]. if the exponent is an integer 3, 4, 5, 6 etc.
it gives the cube the 4th power, 5th, 6th, etc.
If the exponent is 1/3, 1/4, 1/5, 1/6 you calculate the cubic root, the 4th root and so on.
When you use it to calculate the roots, the radicand (the number the root of which you are calculating) must be positive, otherwise you may get the result as a complex number.

The syntax of the command is value [Y to x] (1/ order of root)

Ex: cube root of 27 is entered as 27 [Y to x] (1/3)

SOURCE: my TI BA ii plus calculator is calculating the

Before each calculation of a TVM problem you must fully clear the calculator ... Press [2ND] [CPT] [2ND] [FV]

Best of luck

SOURCE: can you convert decimal to fraction on BA II plus

There is no built-in conversion between decimal and fraction.