Once you have an equation of the form $5y = \text{(some number)}$, what operation will turn $5y$ into just $y$? Apply that operation to both sides.

After you find a value for $y$, plug it back into $5y + 3$ and see if you really get 23.

In Desmos, use $x$ as the variable. Enter the two expressions as separate functions:

• Type y = 5x + 3
• Type y = 23

Look for the point where the line $y = 5x + 3$ and the horizontal line $y = 23$ intersect. Tap that point; the x-coordinate of the intersection is the value that satisfies the original equation $5y + 3 = 23$.

The equation is $5y + 3 = 23$. To start isolating $y$, remove the $+3$ by subtracting 3 from both sides:

This simplifies to:

Now $5y = 20$. To get $y$ alone, divide both sides by 5 (the coefficient of $y$):

So $y = 4$. The value of $y$ that satisfies the equation is 4, which corresponds to choice C.