Question 7 (Multiple Choice, Worth 6 points)

Which of the following is the solution to the equation [tex]$25^{(z-4)}=125$[/tex]?

A. [tex]$z=5.5$[/tex]
B. [tex][tex]$z=3.5$[/tex][/tex]
C. [tex]$z=-2.5$[/tex]
D. [tex]$z=-0.5$[/tex]



Answer :

Certainly! Let's solve the equation [tex]\( 25^{(z-4)} = 125 \)[/tex] step by step.

1. Understanding the bases:
[tex]\[ 25 = 5^2 \quad \text{and} \quad 125 = 5^3 \][/tex]
So, we can rewrite the equation using a common base of 5:
[tex]\[ (5^2)^{(z-4)} = 5^3 \][/tex]

2. Applying the power rule:
[tex]\[ 5^{2(z-4)} = 5^3 \][/tex]

3. Equating the exponents:
Since the bases are the same, we can set the exponents equal to each other:
[tex]\[ 2(z-4) = 3 \][/tex]

4. Solving for [tex]\( z \)[/tex]:
Let's solve the equation [tex]\( 2(z-4) = 3 \)[/tex]:
[tex]\[ 2z - 8 = 3 \][/tex]
[tex]\[ 2z = 11 \][/tex]
[tex]\[ z = \frac{11}{2} \][/tex]

5. Simplifying the answer:
[tex]\[ z = 5.5 \][/tex]

Therefore, the solution to the equation [tex]\( 25^{(z-4)} = 125 \)[/tex] is [tex]\( z = 5.5 \)[/tex].

Among the given options, the correct one is:
[tex]\[ \boxed{z = 5.5} \][/tex]