Using proportions, the multiplication expression to determine the total change in the value of these cars at the dealership is given by:
T = -1,200 x 42.
A proportion is a fraction of a total amount, and the measures are related using a rule of three. Due to this, relations between variables, either direct or inverse proportional, can be built to find the desired measures in the problem.
For this problem, we have that one car depreciated on average -$1,200. We want to find the amount relative to 42 cars, and this amount can be found by the following rule of three.
1 car - -$1,200.
42 cars - $T
Applying cross multiplication, the expression is given by:
T = -1,200 x 42.
More can be learned about proportions at https://brainly.com/question/24372153
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