To determine the first number in the equation [tex]\(2n + 1 = 157\)[/tex], we need to solve for [tex]\(n\)[/tex]. Follow these steps:
1. Start with the equation:
[tex]\[ 2n + 1 = 157 \][/tex]
2. Isolate the term containing [tex]\(n\)[/tex]:
Subtract 1 from both sides of the equation.
[tex]\[ 2n + 1 - 1 = 157 - 1 \][/tex]
[tex]\[ 2n = 156 \][/tex]
3. Solve for [tex]\(n\)[/tex]:
Divide both sides of the equation by 2.
[tex]\[ \frac{2n}{2} = \frac{156}{2} \][/tex]
[tex]\[ n = 78 \][/tex]
Therefore, the first number is 78.
The correct answer is [tex]\( \boxed{78} \)[/tex].
