Once you have an equation of the form $0.5t = 1.5$, what should you divide both sides by to solve for $t$?

After you find $t$, remember the question asks for $t - 3$. Substitute your value of $t$ into $t - 3$ and simplify.

In Desmos, enter y = 0.5x - 1.5 to represent the left side of the equation as a line.

On a new line, enter y = 0 to graph the x-axis, which represents the right side of the equation.

Click the point where the line y = 0.5x - 1.5 intersects y = 0. The x-coordinate of this intersection is the value of $t$ that makes $0.5t - 1.5 = 0$.

Take the x-coordinate you found and, in a new expression line, type that number minus 3 (for example, if the x-coordinate is $k$, type k - 3 using the actual number). The result Desmos displays is the value of $t - 3$.

Start with the equation:

Add $1.5$ to both sides to move the constant term:

Now you have:

Divide both sides by $0.5$:

To divide by a decimal more easily, multiply numerator and denominator by $2$:

So $t = 3$.

The question asks for $t - 3$, not just $t$.

Substitute $t = 3$ into $t - 3$:

So the value of $t - 3$ is $\boxed{0}$.