Write MIPS assembly code for the following: $($need to use sll for multiplication and sll for division, no other instruction allowed$)$

Write machine codes $($in hex$)$ for the following:

Addi $50,$ t$1,-4$

Sub s$1,$ t$1,$ t$2$

Sw s$1,8($s$2)($Find the op codes$/$functions from the book$)$