Question

Which step contains an error using the Commutative Property of Addition in verifying 8+x2+17x−x2+4=10+4x2+10x−4x2+2+7x
?

Step 1: 8+4+x2−x2+17x=10+2+10x−4x2+7x +4x2


Step 2: 8+4+17x+x2−x2=10+2+4x2−4x2+10x+7x


Step 3: 12+17x+x2=12−x2+17x


(1 point)
Responses

Step 2
Step 2

No mistake was made.
No mistake was made.

Step 1
Step 1

Step 3
Step 3
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Answer 1

Step 3.

Reason: From Step 2 both x^2 terms cancel on each side, and 8+4 = 10+2 = 12, 10x+7x = 17x, so both sides should simplify to 12 + 17x. Step 3 incorrectly leaves +x^2 on the left and −x^2 on the right.