After you remove the $+7$, what number should be on the right-hand side of the equation?

Once you have an equation of the form $\tfrac{3}{2}t = \text{(number)}$, how do you isolate $t$? Remember that dividing by a fraction is the same as multiplying by its reciprocal.

In Desmos, enter y = (3/2)x + 7 on one line and y = 31 on another line so you can see where the line from the equation equals 31.

Click on the point where the two graphs intersect; the x-coordinate of this intersection is the value of $t$ that solves the equation.

Start with the equation:

To isolate the term with $t$, subtract 7 from both sides:

This simplifies to:

Now you have:

To undo the multiplication by $\tfrac{3}{2}$, divide both sides by $\tfrac{3}{2}$, which is the same as multiplying by its reciprocal $\tfrac{2}{3}$:

Compute this product:

So the value of $t$ is $16$.