The temperature increased 12 degrees between 9 am and noon. it decreased 9 degrees between noon and 6 pm.

write an expression with three terms to show the change in temperature. let the first term represent the temperature at 9am.

Step-by-step explanation:

Let temperature at noon be x

Temperature at 9am = x

Temperature between 9am and noon = x + 12

Temperature between noon and 6pm = x + 12 - 9 = x+3

{ (x+12) ° - 9°} - x°

Step-by-step explanation:

Let the initial temperature be = x°

It increased by 12° between 9am and 12 = (x+12) °

It decreased by 9° between noon and 6pm = (x+12) ° - 9°

change in temperature will be given by = temperature at 6pm - initial temperature

{ (x+12) ° - 9°} - x°