To solve the equation $3^x - 4 = 6$ using the change of base formula, follow these steps:

Step 1: Isolate the exponential term

First, add 4 to both sides of the equation to isolate the exponential expression:

$3^x - 4 + 4 = 6 + 4$

$3^x = 10$

Step 2: Apply logarithms to solve for $x$

To solve for $x$, take the logarithm of both sides. You can use any logarithm base, but the common logarithm (base 10) or natural logarithm (base $e$) are most common. Let's use the natural logarithm:

$\ln(3^x) = \ln(10)$

Step 3: Use the power rule of logarithms

Apply the power rule of logarithms, which states $\ln(a^b) = b \cdot \ln(a)$,