Jenny is working on simplifying the algebraic expression 3x+21

Question

when x=5
. Her steps are as follows:

Step 1: 35+21

Step 2: 15+21

Step 3: 36

In which step did Jenny make a mistake? What should she have done differently?

(1 point)
Responses

Step 2, Jenny should've calculated the value of 35
to be 243.
Step 2, Jenny should've calculated the value of 3 to the 5th power to be 243.

Step 2, Jenny should've added 3 and 5 to get 8.
Step 2, Jenny should've added 3 and 5 to get 8.

Step 3, 15+21
should be 15⋅21
.
Step 3, 15 plus 21 should be 15 times 21.

Step 1, Jenny should've multiplied 3⋅5
instead of writing 5 as the exponent.
Step 1, Jenny should've multiplied 3 times 5 instead of writing 5 as the exponent.

Answer 1

Jenny made a mistake in Step 1. She incorrectly calculated \(3x\) when she substituted \(x = 5\). Here's the correct calculation:

In Step 1, she should have calculated \(3 \times 5\), which equals \(15\), not \(35\).

So the correct first step should have been: \[ 3 \cdot 5 + 21 = 15 + 21 = 36 \]

The correct response would be: Step 1, Jenny should've multiplied \(3 \cdot 5\) instead of writing 5 as the exponent.