STX - store X in a memory address.
STX Absolute Addressing
This will store the contents of the X register in memory address $2002. Since the entire memory address number is used, this is referred to as absolute addressing.
STX Immediate Addressing
Immediate addressing is used to load a number straight into X, without loading it from memory.
This will load the number 5 into X using a binary number.
This will load 5 into X using a decimal number.
This will load 5 into X using a hexadecimal number.
Zero Page Addressing
This will load the contents of the memory address $0098 into X.