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 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.

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

Answer 1

The mistake Jenny made is in Step 1.

In Step 1, the expression was \( 3x + 21 \) evaluated at \( x = 5 \). Jenny should have correctly calculated this as follows:

1. Multiply \( 3 \) by \( 5 \) (which is \( 3 \cdot 5 = 15 \)).
2. Then add \( 21 \) to this result \( (15 + 21 = 36) \).

Instead, in Step 1, she incorrectly wrote \( 35 + 21 \), which is incorrect since she did not perform the multiplication \( 3 \cdot 5 \) correctly.

So, the correct answer would be that Jenny made a mistake in Step 1 and should have multiplied \( 3 \cdot 5 \) instead.