Select the correct step and statement.

Julian factored the expression [tex]$2x^4 + 2x^3 - x^2 - x$[/tex]. His work is shown below. At which step did Julian make his first mistake, and which statement describes the mistake?

\begin{tabular}{|l|c|}
\hline & [tex]$2x^4 + 2x^3 - x^2 - x$[/tex] \\
\hline Step 1 & [tex]$= x(2x^3 + 2x^2 - x - 1)$[/tex] \\
\hline Step 2 & [tex]$= x[2x^2(x + 1) - 1(x - 1)]$[/tex] \\
\hline Step 3 & [tex]$= x(2x^2 - 1)(x + 1)(x - 1)$[/tex] \\
\hline
\end{tabular}

\begin{tabular}{|l|l|}
\hline Statement 1 & Julian should have factored [tex]$(2x^2 - 1)$[/tex] as a difference of squares. \\
\hline Statement 2 & Julian incorrectly applied the distributive property when factoring out -1. \\
\hline Statement 3 & Julian should have factored [tex]$2x$[/tex] from all terms instead of [tex]$x$[/tex]. \\
\hline Statement 4 & Julian incorrectly factored [tex]$2x^2$[/tex] from the first group of terms. \\
\hline
\end{tabular}



Answer :

Let's carefully analyze Julian's steps:

### Original Expression
[tex]\[ 2x^4 + 2x^3 - x^2 - x \][/tex]

### Step 1:
Julian factored out [tex]\( x \)[/tex] from the original expression:
[tex]\[ 2x^4 + 2x^3 - x^2 - x = x \cdot (2x^3 + 2x^2 - x - 1) \][/tex]
This step is correct.

### Step 2:
Next, Julian attempted to factor by grouping:
[tex]\[ x \cdot (2x^3 + 2x^2 - x - 1) = x \left[ 2x^2(x + 1) - 1(x - 1) \right] \][/tex]
Here we should check his grouping and factoring.

- Group the terms: [tex]\( (2x^3 + 2x^2) \)[/tex] and [tex]\( (-x - 1) \)[/tex]
- Factor [tex]\( 2x^2 \)[/tex] from the first group: [tex]\( 2x^2(x + 1) \)[/tex]
- Factor [tex]\( -1 \)[/tex] from the second group: [tex]\( -1(x - 1) \)[/tex]

Julian's mistake occurs here. When factoring the second group, he didn't apply the distributive property correctly:
[tex]\[ -1(x - 1) \neq 1(x - 1) \][/tex]
It should be:
[tex]\[ -1(x + 1 - 2) = -1(x + 1) - 2 \][/tex]

### Step 3:
Julian attempted to write the final factorized form:
[tex]\[ x \left(2x^2 - 1 \right)(x + 1)(x - 1) \][/tex]

Thus, Julian made his first mistake in Step 2. He incorrectly applied the distributive property when factoring out [tex]\(-1\)[/tex].

### Correct Step and Statement:
- Step 2 is where Julian made his first mistake.
- The mistake is described by Statement 2: Julian incorrectly applied the distributive property when factoring out -1.

Therefore, the correct step and statement are:
[tex]\[ \text{Step: 2, Statement: 2} \][/tex]