Antarctic temperatures

This task is about linear equations that show change in temperature.
scott base antarctica
 
Temperatures at Scott Base are measured at 6:00 a.m. in the morning, and 6:00 p.m. in the evening.
One Wednesday evening the temperature was –25°C. It had risen 13°C since the morning.

Question 2Change answer

a)  This equation shows the temperature change on that Wednesday.
 
t + 13 = – 25
     i) What does t represent in the equation above? 
     ii) What is the value of t? °C

Question 2Change answer

b) This equation describes the change in temperature from that Wednesday evening to the following Thursday morning.
 
 –25 + x = –16
     i)  What was the temperature on Thursday morning? °C
     ii) By how much did the temperature change overnight? °C