Hello, having an issue with the hex code, how does $-0x47 work? i dont understand the negative.

prompt of the question:

After executing each of the following x86-64 Assembly code snippets, (1) what is the content of the rax register in hex (show your calculations/work in hex). (2) what is the status of each of the four flags (ZF, SF, CF, and OF) and why? Explain each flag status/state in details (i.e., discuss reasons why each of those flags is set, cleared, or unaffected). Assume that the initial value stored in rax prior to executing each of the following code snippets is 0.

4) movl \$-0x47, \%eax subb $58,% al