Answer:
17y^2-22y
Step-by-step explanation:
Hope this helps
[tex]\\ \ast\sf\longmapsto 13y^2+9y+4y^2-31y[/tex]
[tex]\\ \ast\sf\longmapsto 13y^2+4y^2+9y-31y[/tex]
[tex]\\ \ast\sf\longmapsto 17y^2-22y[/tex]
[tex]\\ \ast\sf\longmapsto y(17y-22)[/tex]