To determine if \(-1 + 8\) is rational or irrational, we first calculate the expression:
\[ -1 + 8 = 7 \]
Now we need to check whether \(7\) is a rational number. A rational number is defined as any number that can be expressed as the fraction of two integers, where the denominator is not zero.
The number \(7\) can be expressed as:
\[ \frac{7}{1} \]
Since both \(7\) and \(1\) are integers and the denominator is not zero, \(7\) is indeed a rational number.
Thus, \(-1 + 8\) is a rational number.