After substituting $y = 2x + 1$ into $4x - y = 5$, simplify carefully and solve for $x$ step by step.

Once you have $x$ and $y$, be sure to compute $y - x$, not $x - y$. Pay attention to the order of subtraction.

In Desmos, type y = 2x + 1 on one line. On another line, rewrite the second equation in $y$-form: $4x - y = 5$ becomes y = 4x - 5, and type that as well.

Look at the graph and identify the point where the two lines intersect. Click that intersection point to see its coordinates $(x, y)$.

In a new expression line, type y - x using the $x$ and $y$ values from the intersection point (or directly type y1(x_intersect) - x_intersect if you labeled functions). Read the resulting numerical value; that is the value of $y - x$.

We are given the system:

• $y = 2x + 1$
• $4x - y = 5$

Since $y = 2x + 1$, substitute $2x + 1$ for $y$ in the second equation:

$4x - y = 5$ becomes $4x - (2x + 1) = 5$.

Simplify the equation $4x - (2x + 1) = 5$:

2x - 1 = 5

2x = 6

x = 3

Use the first equation $y = 2x + 1$ and plug in $x = 3$:

So the solution to the system is $(x, y) = (3, 7)$.

We are asked for $y - x$.

Using $(x, y) = (3, 7)$:

So the correct answer is 4.