13. \( -7=\frac{x}{-3} \)

To solve the equation \( -7=\frac{x}{-3} \), you can begin by multiplying both sides by \(-3\) to isolate \(x\). This gives you \(x = -7 \times -3\), which simplifies to \(x = 21\). Yay for algebra! Don't forget to check your work! You can plug \(x = 21\) back into the original equation: \( \frac{21}{-3} = -7\). If both sides of the equation match, then the solution is confirmed. Always verify your solutions to avoid any sneaky mistakes!