The rational expression 130x100 x describes the cost in mil

The rational expression 130x/100 - x describes the cost, in millions of dollars, to inoculate x percent of the population against a particular strain of flu. a. Evaluate the expression for x = 40, x = 80, and x = 90. Describe the meaning of each evaluation in terms of percentage inoculated and cost. b. For what value of x is the expression undefined?

Solution

a) 130x/[100-x]

for x=40

it is 130*40/60=260/3=86.66

for x=80

it is 130*80/20= 520

for x=90

it is 130*90/10= 1170

b) For the denominator to be zero, x=100

Hence for x=100, the expression is undefined.