[tex]\begin{gathered} (2x^4-2x^2)+(-2x^4+3x^2)=2x^4-2x^2-2x^4+3x^2 \\ \text{Add like terms:} \\ (2x^4-2x^4)+(-2x^2+3x^2)=0+x^2 \\ \text{Therefore:} \\ (2x^4-2x^2)+(-2x^4+3x^2)=x^2 \end{gathered}[/tex]
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