SAT Question 7a987ae4: Linear Equations In One Variable answer and explanation with Desmos solution

Choice B is correct. Multiplying both sides of the given equation by $5$ yields $2n=50$. Substituting $50$ for $2n$ in the expression $2n-1$ yields $50-1=49$.

Alternate approach: Dividing both sides of $2n=50$ by $2$ yields $n=25$. Evaluating the expression $2n-1$ for $n=25$ yields $2\times 25-1=49$.