Solve 4^x-1=16

$$4 ^ { x - 1 } = 16$$

Solve for x

$$x=3$$

Steps Using Definition of Logarithm

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

$$4^{x-1}=16$$

Take the logarithm of both sides of the equation.

$$\log(4^{x-1})=\log(16)$$

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

$$\left(x-1\right)\log(4)=\log(16)$$

Divide both sides by \log(4).

$$x-1=\frac{\log(16)}{\log(4)}$$

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

$$x-1=\log_{4}\left(16\right)$$

Add 1 to both sides of the equation.

$$x=2-\left(-1\right)$$

Solve for x (complex solution)

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

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