Question

Describe and correct the error a student made when starting to solve the equation 8 ^ (x + 3) = 2 ^ (2x - 5) 8 ^ (x + 3) = 2 ^ (2x - 5) (2 ^ 3) ^ (x + 3) = 2 ^ (2x - 5) 2 ^ (3x + 3) = 2 ^ (2x - 5) Choose the correct answer below A. The student should have divided both sides by 2 ^ 2 to simplify the expression B. The student did not convert 8 to the correct power of 2 C. The student did not distribute 3 in * (2 ^ 3) ^ (x + 3) x + 3 D.The student should have expressed the initial rational exponent as the sum of two rational exponents ..

Answer 1

Answer:

C. is the correct option

C. The student did not distribute 3 in * (2 ^ 3) ^ (x + 3) x + 3

and x = - 14

Step-by-step explanation:

8 ^ (x + 3) = 2 ^ (2x - 5)

Here is how the student solved the equation

8 ^ (x + 3) = 2 ^ (2x - 5)

8 ^ (x + 3) = 2 ^ (2x - 5)

(2 ^ 3) ^ (x + 3) = 2 ^ (2x - 5)

2 ^ (3x + 3) = 2 ^ (2x - 5) -----  This is where the student made the error.

The student did not distribute 3 in * (2 ^ 3) ^ (x + 3).

This is how to solve the equation

8 ^ (x + 3) = 2 ^ (2x - 5)

8 ^ (x + 3) = 2 ^ (2x - 5)

(2 ^ 3) ^ (x + 3) = 2 ^ (2x - 5)

Then, we will 3 distribute in  (2 ^ 3) ^ (x + 3), so that we get

2 ^ (3x +9) = 2 ^ (2x -5)

Since the bases on both sides of the equation are equal, we can equate the powers so that we get

(3x +9) = (2x -5)

Then we will collect like terms

3x - 2x = -5 -9

∴ x = -14

This solution could be better written in this format

$8^{x+3} = 2^{2x-5} \\2^{3} ^{(x+3)} = 2^{2x-5}\\2^{(3x+9)} = 2^{2x-5}\\{(3x+9)} = {2x-5} \\3x-2x= -5-9\\x = -14$