Isabella was asked to determine whether f(x)=3x4+6x−2 is even, odd, or neither. Here is her work. Step 1: Find the expression for f(−x). f(−x)=3(−x)4+6x−2=3x4+6x−2 Step 2: Check if f(−x) is equal to f(x) or −f(x). f(−x)=f(x), and f(−x)≠−f(x). Step 3: Conclude that f(−x) is equivalent to f(x), so f must be even. Is Isabella's work correct? If not, what is the first step where Isabella made a mistake? Isabella's work is correct.

Isabella's work is not correct. She made her first mistake in step 3.

Isabella's work is not correct. She made her first mistake in step 2.

Isabella's work is not correct. She made her first mistake in step 1.