Answer: Third option.
Explanation:
We need to remember that:
![a^m=a^n\\\\m=n](https://img.qammunity.org/2020/formulas/mathematics/middle-school/6u62ha5qf1j45sw1u0kl5rgsrgt1joluum.png)
In this case, given this expression:
![4^x](https://img.qammunity.org/2020/formulas/mathematics/middle-school/y4l8e44evsdzcljnyzasrk0jj1wx1y9wbz.png)
![=8^(( x- 1))](https://img.qammunity.org/2020/formulas/mathematics/middle-school/m1a1jso1izpl7ij55h9bkvk6ik3efs967l.png)
We need to descompose 4 and 8 into their prime factors:
![4=2*2=2^2](https://img.qammunity.org/2020/formulas/mathematics/middle-school/lkc60z6oxjt2mg47se396ejoisy3sh38uz.png)
![8=2*2*2=2^3](https://img.qammunity.org/2020/formulas/mathematics/high-school/dwwwmmnp01haylrulkrw1pz0u5teazurt9.png)
Rewriting the expression:
![2^(2x)](https://img.qammunity.org/2020/formulas/mathematics/middle-school/sz5zcvzszlrd297gtyrq7kzh0mry7ie090.png)
![=2^(3(x - 1) )](https://img.qammunity.org/2020/formulas/mathematics/middle-school/hk5v80cjr5qtn90y0znr7ylgm7e57zgtgr.png)
Then:
![2x = 3(x - 1)](https://img.qammunity.org/2020/formulas/mathematics/middle-school/v1txdvidkezw3iubxh7iimzluoosnofmaa.png)
Finally, applying Distributive property on the right side and solving for "x", we get:
![2x=3x-3\\\\3=3x-2x\\\\x=3](https://img.qammunity.org/2020/formulas/mathematics/middle-school/ivsau3ldmldcjvfx5pe9318el4htm34ier.png)