Using $2\text{'}$s complement arithmetic and assuming $6-$bits including sign bit perform: $(-8{)}_{10}+(-17{)}_{10}$

Calculate the followings:

$2\text{'}$s Complement for $(-8{)}_{10}=(,{)}_2$

$2\text{'}$s Complement for $(-17{)}_{10}=(,{)}_2$

Sum $($without carry$)=()2$

$.$ What is the result in signed magnitude? $({)}_2$