I REALLY NEED HELP PLEASE

Answer:
10
Step-by-step explanation:
given
[tex] \frac{s + ( - 7)}{ - 1} [/tex]
we first need to simplify the expression before we find it's value when s=-3
positive times negative=negative
so the equation becomes
[tex] \frac{s - 7}{ - 1} [/tex]
substituting s=-3 into the equation.
[tex] \frac{ - 3 - 7}{ - 1} [/tex]
=
[tex] \frac{ - 10}{ - 1} [/tex]
=the negatives cancel out leaving
[tex]= 10[/tex]