Answer
a. unhealthy.
b. not unhealthy.
Work Step by Step
The formula that describes unhealthy body temperature is given as:
$ |x-98.6|\geq 1.5$
We plug in the given temperature values and if the inequality proves true, then the temperature is unhealthy.
a. Since $|97-98.6|=1.6 \ge 1.5$, then the temperature of 97°F is unhealthy.
b. Since $|100-98.6|=1.4 \lt 1.5$, then the temperature of 100°F is not unhealthy.