Solve 2^x+3=128

$$2 ^ { x + 3 } = 128$$

Solve for x

$$x=4$$

Steps Using Definition of Logarithm

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

$$2^{x+3}=128$$

Take the logarithm of both sides of the equation.

$$\log(2^{x+3})=\log(128)$$

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

$$\left(x+3\right)\log(2)=\log(128)$$

Divide both sides by \log(2).

$$x+3=\frac{\log(128)}{\log(2)}$$

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

$$x+3=\log_{2}\left(128\right)$$

Subtract 3 from both sides of the equation.

$$x=7-3$$

Solve for x (complex solution)

$$x=\frac{i\times 2\pi n_{1}}{\ln(2)}+4$$

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