What is the solution to [tex]$4+5 e^{x+2}=11$[/tex]?

A. [tex]$x=\ln \frac{7}{5}-2$[/tex]
B. [tex][tex]$x=\ln \frac{7}{5}+2$[/tex][/tex]
C. [tex]$x=\ln 35-2$[/tex]
D. [tex]$x=\ln 35+2$[/tex]



Answer :

To solve the equation [tex]\( 4 + 5e^{x+2} = 11 \)[/tex], follow these steps:

1. Isolate the exponential expression:
Start by subtracting 4 from both sides of the equation to isolate the term involving the exponential function:
[tex]\[ 4 + 5e^{x+2} = 11 \implies 5e^{x+2} = 11 - 4 \implies 5e^{x+2} = 7 \][/tex]

2. Divide by 5:
Divide both sides of the equation by 5 to further isolate the exponential function:
[tex]\[ e^{x+2} = \frac{7}{5} \][/tex]

3. Take the natural logarithm of both sides:
To solve for [tex]\( x \)[/tex], take the natural logarithm (ln) of both sides. Recall that [tex]\( \ln(e^y) = y \)[/tex]:
[tex]\[ \ln(e^{x+2}) = \ln\left(\frac{7}{5}\right) \][/tex]

4. Simplify using properties of logarithms:
On the left side, use the property that [tex]\( \ln(e^y) = y \)[/tex]:
[tex]\[ x + 2 = \ln\left(\frac{7}{5}\right) \][/tex]

5. Isolate [tex]\( x \)[/tex]:
Subtract 2 from both sides to solve for [tex]\( x \)[/tex]:
[tex]\[ x = \ln\left(\frac{7}{5}\right) - 2 \][/tex]

Now, let's compare this form to the given options:

- [tex]\( x = \ln\left(\frac{7}{5}\right) - 2 \)[/tex]
- [tex]\( x = \ln\left(\frac{7}{5}\right) + 2 \)[/tex]
- [tex]\( x = \ln 35 - 2 \)[/tex]
- [tex]\( x = \ln 35 + 2 \)[/tex]

The correct option based on our step-by-step solution is:
[tex]\[ x = \ln\left(\frac{7}{5}\right) - 2 \][/tex]

The numerical value for this option can be evaluated and is approximately [tex]\(-1.66353\)[/tex].

So, the solution to the equation is:
[tex]\[ x = \ln\left(\frac{7}{5}\right) - 2 \][/tex]
and this corresponds to option [tex]\(\boxed{x = \ln\left(\frac{7}{5}\right) - 2}\)[/tex].