What happens if you add the left-hand sides of the two equations together and also add the right-hand sides together? Simplify carefully.

After you combine the equations, check if the left-hand side can be factored to show $x - 3y$ as a factor. Then solve for that factor.

In Desmos, enter the two equations on separate lines:

• 11x - 3y = 5
• -8x - 6y = -25 Desmos will show the point where the two lines intersect; note the coordinates $(x,y)$ of that intersection.

On a new line in Desmos, type the expression x - 3y, but replace $x$ and $y$ with the intersection coordinates you found (for example, if the intersection is (a, b), type a - 3b). The resulting value shown by Desmos is the value of $x - 3y$.

You are not asked to find $x$ and $y$ separately. The question only wants the value of $x - 3y$. This means you should look for a way to combine the equations so that $x - 3y$ appears as a factor.

Add the left-hand sides and right-hand sides of the two equations:

Simplify both sides:

• Combine $x$-terms: $11x + (-8x) = 3x$.
• Combine $y$-terms: $-3y + (-6y) = -9y$.
• Combine constants: $5 + (-25) = -20$.

So you get:

Factor the left side of $3x - 9y$:

So the equation becomes:

Now isolate $x - 3y$ by dividing both sides of the equation by 3:

So the value of $x - 3y$ is $-20/3$, which corresponds to choice D.