Answer:
y⁴ - 2y²
General Formulas and Concepts:
<u>Pre-Algebra</u>
<u>Algebra I</u>
Step-by-step explanation:
<u>Step 1: Define</u>
4y⁴ - (3y² + 3y⁴) + y²
<u>Step 2: Simplify</u>