Answer
(a) $20^{\circ}C$, $293K$
(b) $109K$, $-263^{\circ}F$
(c) $-273^{\circ}C$, $-460^{\circ}F$
Work Step by Step
Recall our conversion formulas:
$^{\circ}C=(^{\circ}F-32) * \dfrac{5}{9}$
$^{\circ}F =( ^{\circ}C * \dfrac{9}{5})+32$
$K = {^{\circ}C}+273$
$^{\circ}C = K-273$
$(a)$ $68^{\circ}C$
$^{\circ}C=(68^{\circ}F-32) * \dfrac{5}{9}$
$20^{\circ}C$
$K = {20^{\circ}C}+273$
$293K$
$(b) -164^{\circ}C$
$K = {-164^{\circ}C}+273$
$109K$
$^{\circ}F =(-164 ^{\circ}C * \dfrac{9}{5})+32$
$-263^{\circ}F$
$(c) 0K$
$^{\circ}C = 0K-273$
$-273^{\circ}C$
$^{\circ}F =( -273^{\circ}C * \dfrac{9}{5})+32$
$-460^{\circ}F$