Question

Determine the value of x to the nearest thousandth in the equation 8(2)^x+3=48

Answer 1

You probably mean either

$8\cdot2^x + 3 = 48$

or

$8\cdot2^{x+3} = 48$

Write 8 = 2³, so that in the first interpretation,

$8\cdot2^x = 2^3 \cdot 2^x = 2^{x + 3}$

and in the second,

$8\cdot2^{x+3} = 2^3 \cdot 2^{x+3} = 2^{x + 6}$

Then in the first interpretation, we have

$2^{x + 3} + 3 = 48 \implies 2^{x + 3} = 45 \implies x + 3 = \log_2(45) \implies x = \log_2(45) - 3 \approx \boxed{2.492}$

Otherwise, the second interpretation gives

$2^{x + 6} = 48 \implies x + 6 = \log_2(48) \implies x = \log_2(48) - 6 \approx -0.415$