Question

What's the answer and how do you do it?

Answer 1

the vertical asymptotes for a rational expression, occur at the values of "x" that make the denominator 0, and therefore the expression undefined.

what are those anyway?  simple, just set the denominator to 0, solve for "x", and that will spit them out.

x + 4 = 0
x = -4

there, if "x" ever becomes -4, then the fraction turns to $\bf \cfrac{1}{x+4}\implies \cfrac{1}{-4+4}\implies \stackrel{und efined}{\cfrac{1}{0}}$

thus, that's where the vertical asymptote is at, x = -4.

Answer 2

A vertical asymptote is when y gets higher and higher or lower and lower without stopping around a certain point. In a fraction one way this can happen is when there is a point where the denominator is 0, as when it gets close to 0 it gets bigger and bigger, and anything over 0 is undefined. Therefore the answer is A as 1/4-4 is 1/0 and an asymptote