SAT Question fa80893a: Linear Equations In One Variable answer and explanation with Desmos solution

It's given that $2x+3=9$. Multiplying each side of this equation by $3$ yields $3\left(2x+3\right)=3\left(9\right)$, or $6x+9=27$. Subtracting $10$ from each side of this equation yields $6x+9-10=27-10$, or $6x-1=17$. Therefore, the value of $6x-1$ is $17$.