For the equation, we only know that x+3= 12 or x+3 = -12.
(X+3=12) First possible solution. X +3 = 12 Add -3 to each side which will get rid of 3 and leave X= 12-3 Which leads to X= 9. (X+3= -12) Second possible solution. X+3= -12 Add -3 to both sides which will get rid of 3 and leave x= -12 -3 Which leads to x= -15
The temperature will remain constant over time. This means the slope of the graph will be constant from one point of the graph to the other, which cancels out to zero.
