### Home > PC3 > Chapter 5 > Lesson 5.2.2 > Problem5-78

5-78.

Estimate the solution to each of these equations without a calculator and justify your estimate.

1. $20^x=316$

Since $20^2=400$, $x$ must be less than $2$.

1. $7.3^x=4.81$

$7.3^1=7.3$, so $x$ must be less than $1$.

1. $160(0.5)^x=8$

$\left(\frac{1}{2}\right)^x=\frac{8}{160}=\frac{1}{20}$

$\left(\frac{1}{2}\right)^4=\frac{1}{16}$