Final answer:
To solve the equation 5^x-4 = 7 using the change of base formula logb y = log y / log b, we rewrite the equation as log 5 (7) = x - 4. By applying the change of base formula, we find that x is approximately 4.827.
Step-by-step explanation:
To solve the equation 5^x-4 = 7 using the change of base formula logb y = log y / log b, we can rewrite the equation as log 5 (7) = x - 4.
Using the change of base formula, we have log 7 / log 5 = x - 4.
Adding 4 to both sides, we get x = log 7 / log 5 + 4. Evaluating this expression, we find that x is approximately 4.827. Therefore, the correct value is 4.827.