Answer
Sunday:$-9,9$
Monday:$-3,3$
Tuesday: $0,0$
Wednesday: $5,5$
Thursday: $9,9$
Friday: $1,1$
Saturday: $-1,1$
$T_o - T_G $ gives more information
Work Step by Step
During Sunday:
$$T_o - T_G = 68-77 = -9 F^{\circ}\\ |T_o-T_G| = 9^{\circ}$$
During Monday:
$$T_o - T_G = 72-75 = 3 F^{\circ}\\ |T_o-T_G| =3^{\circ}$$
During Tuesday:
$$T_o - T_G = 74-74 = 0 F^{\circ}\\ |T_o-T_G| = 0^{\circ}$$
During Wednesday:
$$T_o - T_G = 80-75 = 5 F^{\circ}\\ |T_o-T_G| =5^{\circ}$$
During Thursday:
$$T_o - T_G =77-68 = 9 F^{\circ}\\ |T_o-T_G| = 9 ^{\circ}$$
During Friday:
$$T_o - T_G =71-70 =1 F^{\circ}\\ |T_o-T_G| = 1 ^{\circ}$$
During Saturday:
$$T_o - T_G =70-71 = -1 F^{\circ}\\ |T_o-T_G| = 1 ^{\circ}$$
$T_o - T_G $ gives more information as it indicates which city has the higher temperature.
