Hey there!
[tex]-8+(-15)[/tex]
To easily solve this, try removing the negative and add 8 + 15.
[tex]8+(15)=23[/tex]
Now add back the negative.
[tex]-8+(-15)=-23\\-23(ANSWER)[/tex]
Hope this helps and have a great weekend!
[tex]\text {-TestedHyperr}[/tex]