To solve the equation [tex]\(-1 + \square = -8\)[/tex] and find the integer that makes the addition sentence true, follow these steps:
1. Start with the given equation:
[tex]\[
-1 + \square = -8
\][/tex]
2. To isolate the [tex]\(\square\)[/tex] on one side of the equation, we need to eliminate the [tex]\(-1\)[/tex] on the left side. To do this, we add [tex]\(1\)[/tex] to both sides of the equation. Adding [tex]\(1\)[/tex] to both sides helps balance the equation and isolate [tex]\(\square\)[/tex].
3. Perform the addition on the left side:
[tex]\[
-1 + 1 + \square = -8 + 1
\][/tex]
4. Simplify both sides:
[tex]\[
0 + \square = -7
\][/tex]
which simplifies to:
[tex]\[
\square = -7
\][/tex]
Therefore, the integer that makes the equation [tex]\(-1 + \square = -8\)[/tex] true is [tex]\(\boxed{-7}\)[/tex].
