Question: If $ST = 2x + 31$ and $SV = 7x + 26$, find the value of $x$ in parallelogram $TUVW$.
1. **State the problem:** We are given a parallelogram $TUVW$ with diagonals intersecting at point $S$. The segments $ST$ and $SV$ are parts of the diagonals.
2. **Important property:** In a parallelogram, the diagonals bisect each other. This means that $S$ is the midpoint of both diagonals, so $ST = SV$.
3. **Set up the equation:** Since $ST = SV$, we have:
$$2x + 31 = 7x + 26$$
4. **Solve for $x$:**
Subtract $2x$ from both sides:
$$\cancel{2x} + 31 = 7x - \cancel{2x} + 26 \implies 31 = 5x + 26$$
Subtract $26$ from both sides:
$$31 - 26 = 5x + \cancel{26} - \cancel{26} \implies 5 = 5x$$
Divide both sides by $5$:
$$\frac{5}{\cancel{5}} = \frac{5x}{\cancel{5}} \implies 1 = x$$
5. **Final answer:**
$$\boxed{1}$$
Thus, the value of $x$ is $1$.