How do you graph f(x)=(4(x+1))/(x(x-4)) using holes, vertical and horizontal asymptotes, x and y intercepts?

1 Answer
Jul 19, 2018

See answer below

Explanation:

Given: f(x) = (4(x+1))/(x(x-4))

This type of equation is called a rational (fraction) function.

It has the form: f(x) = (N(x))/(D(x)) = (a_nx^n + ...)/(b_m x^m + ...),

where N(x)) is the numerator and D(x) is the denominator,

n = the degree of N(x) and m = the degree of (D(x))

and a_n is the leading coefficient of the N(x) and

b_m is the leading coefficient of the D(x)

Step 1 factor : The given function is already factored.

Step 2, cancel any factors that are both in (N(x)) and D(x)) (determines holes):

The given function has no holes " "=> " no factors that cancel"

Step 3, find vertical asymptotes: D(x) = 0

vertical asymptote at x = 0 " and x = 4

Step 4, find horizontal asymptotes:
Compare the degrees:

If n < m the horizontal asymptote is y = 0

If n = m the horizontal asymptote is y = a_n/b_m

If n > m there are no horizontal asymptotes

In the given equation: n = 1; m = 2 " "=> y = 0

horizontal asymptote is y = 0

Step 5, find x-intercept(s) : N(x) = 0

4(x + 1) = 0; " "x + 1 = 0 " "=> x"-intercept" (-1, 0)

Step 5, find y-intercept(s): x = 0

f(0) = (4(1))/(0(-4)) = "undefined"

no y-intercept.

graph{(4(x+1))/(x(x-4)) [-10, 10, -5, 5]}