9. what is the solution for the following question? :))

[tex]\\ \sf\longmapsto -5x+x+9=-4x+12[/tex]
[tex]\\ \sf\longmapsto -4x+9=-4x+12[/tex]
[tex]\\ \sf\longmapsto -4x+4x=12-9[/tex]
[tex]\\ \sf\longmapsto 0=3[/tex]
[tex]\\ \sf\longmapsto \Phi[/tex]