Jenny is working on simplifying the algebraic expression 3^x + 21 when x = 5. Her steps are as follows:

Question

Step 1: 3^5 + 21
Step2: 15 + 21
Step3: 36
In which step did Jenny make a mistake? What should she have done differently?
A) Step 2, Jenny should've added 3 and 5 to get 8.
B) Step 3, 15 + 21 should be 15 x 21
C) Step 1, Jenny should've multiplied 3⋅5 instead of writing 5 as the exponent.
D) Step 2, Jenny should've calculated the value of 3^5 to be 243.

Answer 1

Jenny made a mistake in Step 2. She should have calculated \( 3^5 \) correctly, which equals 243, not 15.

So, the correct option is:

D) Step 2, Jenny should've calculated the value of 3^5 to be 243.

The correct calculation should have been:

1. \( 3^5 + 21 \)
2. \( 243 + 21 \)
3. \( 264 \) (which is the correct simplified result).