### Home > PC3 > Chapter 5 > Lesson 5.2.3 > Problem5-85

5-85.

Solve each exponential equation.

1.  $200(1.05)^x=1000$

Divide both sides by $200$. $(1.05)^x=5$

Take the log of both sides to undo the exponent.
$\log(1.05)^x=\log(5)$
$x\log(1.05)=\log(5)$

Divide both sides by $\log(1.05)$.

1.  $20(2.5)^x−400=600$

1. Add $400$ to both sides.
2. Follow a process similar to the steps in part (a).