Solve 0.2^x=125

$${ 0.2 }^{ x } =125$$

Solve for x

$$x=-3$$

Steps Using Definition of Logarithm

Use the rules of exponents and logarithms to solve the equation.

$$0.2^{x}=125$$

Take the logarithm of both sides of the equation.

$$\log(0.2^{x})=\log(125)$$

The logarithm of a number raised to a power is the power times the logarithm of the number.

$$x\log(0.2)=\log(125)$$

Divide both sides by \log(0.2).

$$x=\frac{\log(125)}{\log(0.2)}$$

By the change-of-base formula \frac{\log(a)}{\log(b)}=\log_{b}\left(a\right).

$$x=\log_{0.2}\left(125\right)$$

Solve for x (complex solution)

$$x=-\frac{i\times 2\pi n_{1}}{\ln(5)}-3$$

$$n_{1}\in \mathrm{Z}$$