For this case we must resolve the following expression:
[tex]-1-8 + \frac {9} {- 1}[/tex]
The division has priority over addition and subtraction, then[tex]\frac {9} {- 1} = - 9[/tex]:
[tex]-1-8-9[/tex]
Knowing that equal signs are added and the same sign is placed:
[tex]-1-8-9 = -18[/tex]
Answer:
[tex]-1-8 + \frac {9} {- 1} = - 18[/tex]
