## College Algebra (6th Edition)

a. $\frac{130(40)}{100-40}$ = $\frac{5200}{60}$ = 86.67 $86.67\times1,000,000$ = 86,670,000 $\frac{130(80)}{100-80}$ = $\frac{10400}{20}$ = 520 $520\times1,000,000$ = 520,000,000 $\frac{130(90)}{100-90}$ = $\frac{11700}{10}$ = 1170 $1170\times1,000,000$ = 1,170,000,000 b. If x = 100, the denominator would be 100-100 which equals zero. a Zero in the denominator causes the expression to be undefined. c. The cost increases rapidly; it is impossible to inoculate 100% of the population.