SAT Question 092ad67d: Systems of Linear Equations answer and explanation with Desmos solution

Choice B is correct. Adding the first equation to the second equation in the given system yields $\left(x+2y\right)+\left(x-2y\right)=6+4$, or $\left(x+x\right)+\left(2y-2y\right)=10$. Combining like terms in this equation yields $2x=10$. Dividing both sides of this equation by $2$ yields $x=5$. Thus, the value of $x$ is $5$.