Which shows how to solve the equation [tex]-\overline{5}^x=80[/tex] for [tex]x[/tex] in one step?

A. [tex]-\frac{4}{5}\left(\frac{5}{4}\right) x=80\left(\frac{5}{4}\right)[/tex]
B. [tex]-\frac{4}{5}\left(-\frac{5}{4}\right) x=80\left(-\frac{5}{4}\right)[/tex]
C. [tex]\frac{4}{5}(-5) x=80(-5)[/tex]
D. [tex]\frac{4}{5}(5) x=80(5)[/tex]



Answer :

To solve the equation [tex]\(-5^x = 80\)[/tex] for [tex]\(x\)[/tex], you need to isolate [tex]\(x\)[/tex]. Let me walk you through the steps:

1. Understand the Equation: The original equation is [tex]\(-5^x = 80\)[/tex].

2. Isolate the Term Involving [tex]\(x\)[/tex]: To make the equation easier to solve, we need to isolate the exponential term [tex]\(5^x\)[/tex].

3. Remove Negative Sign: Since the left side of the equation is negative, multiply both sides of the equation by [tex]\(-1\)[/tex]:
[tex]\[ -(-5^x) = -80 \][/tex]
Which simplifies to:
[tex]\[ 5^x = -80 \][/tex]

4. Logarithmic Transformation: Apply the natural logarithm (ln) to both sides of the equation to solve for [tex]\(x\)[/tex]:
[tex]\[ \ln(5^x) = \ln(80) \][/tex]

5. Use Logarithm Properties: Use the property [tex]\(\ln(a^b) = b \ln(a)\)[/tex]:
[tex]\[ x \ln(5) = \ln(80) \][/tex]

6. Solve for [tex]\(x\)[/tex]: Divide both sides by [tex]\(\ln(5)\)[/tex]:
[tex]\[ x = \frac{\ln(80)}{\ln(5)} \][/tex]

7. Complex Solution: Since [tex]\(5^x\)[/tex] is real and positive, if we introduce the complex logarithm, we will consider both the real and imaginary parts:
[tex]\[ x = \frac{\ln(80) + i\pi}{\ln(5)} \][/tex]

Taking all these steps into account, the solution to the equation [tex]\(-5^x = 80\)[/tex] is:
[tex]\[ x = \frac{\ln(80) + i\pi}{\ln(5)} \][/tex]
Therefore, the step-by-step solution gives us the answer:
[tex]\[ x = \frac{\log(80) + i\pi}{\log(5)}. \][/tex]