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5 votes
1. Solve the following equation. Do not use a calculator. Express the answer in EXACT form. \( 2^{3 x-4}=5(3)^{-x+4} \) Applying \( e x p 0 n e n d \) rule 1 (. ท

asked
User Dan Tao
by
8.7k points

1 Answer

3 votes

Answer:

x = log(6480)/log(24)

Explanation:

You want the solution to the equation 2^(3x-4) = 5(3^(-x+4)).

One base

We can write the equation using one exponential term like this:

2^(3x)·2^(-4) = 5·3^(-x)·3^4

(2^3)^x/16 = 5·81/3^x

(8^x)(3^x) = 16·5·81

24^x = 6480

Logs

Taking logarithms, we have ...

x·log(24) = log(6480)

x = log(6480)/log(24)

__

Additional comment

The numerical value of x is about 2.76158814729.

The relevant rules of exponents are ...

(a^b)(a^c) = a^(b+c)

a^-b = 1/a^b

(a^b)^c = a^(bc)

<95141404393>

answered
User Rintoul
by
8.0k points
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