Please help it’s needed

very easy
[tex]\displaystyle\ (f-g)(x)=f(x)-g(x)=4x^2-5x-3x^2-6x+4=\boxed{x^2-11x+4}[/tex]
[tex]\\ \sf\longmapsto f(x)=4x^2-5x[/tex]
[tex]\\ \sf\longmapsto g(x)=3x^2+6x-4[/tex]
Now
[tex]\\ \sf\longmapsto (f-g)(x)[/tex]
[tex]\\ \sf\longmapsto f(x)-g(x)[/tex]
[tex]\\ \sf\longmapsto 4x^2-5x-(3x^2+6x-4)[/tex]
[tex]\\ \sf\longmapsto 4x^2-5x-3x^2-6x+4[/tex]
[tex]\\ \sf\longmapsto x^2-11x+4[/tex]