SAT Question 55447be2: Systems of Linear Equations answer and explanation with Desmos solution

The given system of equations can be solved by the substitution method. The first equation in the given system of equations is $y=\frac{1}{3}x-14$. Substituting $\frac{1}{3}x-14$ for $y$ in the second equation in the given system yields $\frac{1}{3}x-14=-x+18$. Adding $14$ to both sides of this equation yields $\frac{1}{3}x=-x+32$. Adding $x$ to both sides of this equation yields $\frac{4}{3}x=32$. Multiplying both sides of this equation by $\frac{3}{4}$ yields $x=24$.