Remember that to find the vertical asymptotes of rational functions, we just need to set the denominator equal to zero and solve for the variable, in this case [tex]x[/tex], so lets do it:
[tex](x-4)(x+1)=0[/tex]
[tex]x=4,x=-1[/tex]
As you can see, our rational functions has 2 vertical asymptotes: [tex]x=4[/tex] and [tex]x=-1[/tex]
