SAT Question 39617468: Linear Equations In Two Variables answer and explanation with Desmos solution

Choice C is correct. It’s given that the equation $x+y=350$ relates the total number of maple trees, $x$, and the total number of birch trees, $y$, planted in a $14$ -acre forest preserve. It’s also given that $245$ maple trees were planted in the forest preserve. Substituting $245$ for $x$ in the given equation yields $245+y=350$. Subtracting $245$ from both sides of this equation yields $y=105$. Therefore, $105$ birch trees were planted in the forest preserve.