Using Balance

Use balance to solve for the variables in the following equations:

1. If $x+2=12$, what is $x$?
2. If $x=5$, what is $2x$?
3. If $x+21=80$, what is $2(x+21)$?
4. If $x=25$ what is $\sqrt{x}$?
5. If $\dfrac{x}{5}=3$, what is $x$?
6. If ${x}=-9$, what is $\dfrac{x}{3}$?
7. If ${x}=\dfrac{1}{2}$, what is $2x$?
8. If ${x}=-4$, what is $x^2$?
9. If ${x}=8$, what is $x^3$?
10. If $ab=12$, what is $3ab$?