Answer:
A. x = -2.133
Step-by-step explanation:
1. Simplify: [tex]ln(21^{x+3}) = ln(14)\\[/tex]
2. Use the formula ([tex]ln(a^c)=c*ln(a)[/tex]): [tex](x+3) * ln(21) = ln(14)[/tex]
3. Multiply each term by ln(21): [tex]ln(21)x + 3ln(21) = ln(14)[/tex]
4. Move constant to the right: [tex]ln(21)x = ln(14)-3ln(21)[/tex]
5. Divide both sides: [tex]x=\frac{ln(14)}{ln(21)}-3[/tex]
[tex]x=-2.133[/tex]
