Once you have an equation of the form $5y = \text{(number)}$, what operation will isolate $y$?

After you find $y$, plug that value into $8y$. Remember that $8y$ means $8$ times $y$, not $8$ plus $y$.

In Desmos, type y = 5x - 15 to graph the line. Then find the x-intercept (where the graph crosses the x-axis). The x-coordinate of this intercept is the value of $y$ that satisfies $5y - 15 = 0$.

Once you know the x-value from the intercept, type 8 * (that x-value) into Desmos (for example, if the x-intercept is 3, type 8*3). The output is the value of $8y$.

Start with the equation:

Add 15 to both sides to move the constant term:

Now divide both sides of $5y = 15$ by 5 to get $y$ alone:

You found that $y = 3$. Substitute this value into $8y$:

So, the value of $8y$ is 24.