Answer:
4z
Step-by-step explanation:
-2z² + 4z + 2z²
Combine like terms
-2z^2 + 2z^2 +4z
0z^2 +4z
4z
[tex]\\ \sf\longmapsto -2z^2+4z+2z^2[/tex]
[tex]\\ \sf\longmapsto -2z^2+2z^2+4z[/tex]
[tex]\\ \sf\longmapsto (-2+2)z^2+4z[/tex]
[tex]\\ \sf\longmapsto 0z^2+4z[/tex]
[tex]\\ \sf\longmapsto 4z[/tex]