Coding and Decoding Questions

If 3*1 = 20, 6*1 = 50 and 2*6 = -40, then find the value of 5*8 = ?

In a certain code language, "COPIOUS" is written as "2345389" and "GENEROUS" is written as "16760389". How is "PIGEON" written in that code language?

In a certain code language, "OPTIMIST" is written as "LKRNRGHG". How is "PESSIMIST" written in that code language?

If SYSTEM is written as RXRSDL.
How can CORRECT be written in that code?

If RESEARCH is $#!#%$&@ then SCARE is

In the following question, which one set of letters when sequentially placed at the gaps in the given letter series shall complete it?
c_e_cd_f_d_f

In a code language, if LUCK is written as L2U1C3K1, then what is the last digit for the code for XEROX in that same language?

If 1∆-5=5, 4∆7=-28 and -1∆-3=-3, then find the value of 8∆-8 =?