Pearson Algebra 2 Common Core, 2011
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Pearson Algebra 2 Common Core, 2011 View details
End-of-Course Assessment

Exercise 12 Page 965

Rational functions are undefined at their vertical asymptotes.

F

Practice makes perfect

We want to find the function that is best represented by the given graph.

Notice that this is a rational function with a vertical asymptote at x= 1. This means that the function is undefined for x= 1. By knowing this we can write the denominator of our equation. x=1 ⇒ x-1=0We need to have (x-1) as a product in the denominator. This eliminates the options G and I. Now, let's write our partial equation considering the remaining options F and H. y = ax+ b/x-1 Since we know the y-intercept ( 0, -1), we can find the value of b by substituting x= 0 and y= -1 into the above equation. Let's do it!

y=ax+b/x-1
-1=a* 0+b/0-1
â–¼
Solve for b
-1 = b/0-1
-1 = b/-1
1=b
b=1

We found that the value of b is equal to 1. y=ax+ 1/x-1 Next we will use the other point, (2,1), to find the value of a. Let's substitute x= 2 and y= 1 into the above equation and solve for a.

y=ax+1/x-1
1=a* 2+1/2-1
â–¼
Solve for a
1=a* 2+1/1
1=a* 2+1
0=a* 2
0=a
a=0

With the values of a and b, we can complete our function. y=0* x+ 1/x-1 ⇔ y=1/x-1 Therefore, the answer is option F.