Question

raul tried to evaluate an expression step by step.

$3 - (-5) - 7$

$= 3 + 5 - 7$ \quad step 1

$= 3 + 2$ \quad \quad step 2

$= 5$ \quad \quad \quad step 3

find rauls first mistake.

choose 1 answer:

\\(\bigcirc\\) the opposite of \\(-5\\) is \\(-5\\), not \\(5\\).

\\(\bigcirc\\) \\(5\\) minus \\(7\\) equals \\(-2\\), not \\(2\\).

\\(\bigcirc\\) \\(3\\) plus \\(2\\) equals \\(6\\), not \\(5\\).

Explanation:

Step1: Analyze Step 1

The expression is \(3 - (-5) - 7\). Subtracting a negative is adding the positive, so \(3 - (-5)=3 + 5\), which is correct. So Step 1 is right.

Step2: Analyze Step 2

After Step 1, we have \(3 + 5 - 7\). First, calculate \(3 + 5 = 8\), then \(8 - 7\). But Raul did \(5 - 7 = 2\) (wrongly, it should be \(5 - 7=-2\)) and then \(3 + 2\). So the mistake is in Step 2: \(5 - 7\) equals \(-2\), not \(2\).

Step3: Analyze Step 3 (not needed as mistake is in Step 2)

Answer:

B. 5 minus 7 equals -2, not 2.