Answer
a. $-0.4^{\circ} F$.
b. $-27.8^{\circ} C$.
Work Step by Step
a. Use the formula on page 362.
$$\frac{9}{5}(-18^{\circ} C) + 32 = -0.4^{\circ} F $$
b. Use the formula on page 362.
$$\frac{5}{9}(-18^{\circ} F – 32) = -27.8^{\circ} C $$