Question

in suburbs of large cities,15 new residents move in each year. of those 15, three will move away each year. which of the of the following best describes the meaning of 60, from the expression: 5(15 + (-3)) = 60? a each year 60 new residents move into the suburb. b after five years, 60 new residents have already moved out of a certain suburb. c after five years, there are 60 new residents in a suburb. d over five years, 60 residents first move in, then move out of the suburb.

Explanation:

Step1: Analyze the expression

The expression \(5(15+(- 3))\) represents the total number of new residents over 5 years.

Step2: Calculate the net change per year

\(15+(-3)=15 - 3=12\) (net new residents per year).

Step3: Calculate the total over 5 years

\(5\times12 = 60\). This means after 5 years, there are 60 new residents in the suburb.

Option A is wrong because \(15+(-3)=12\) is the net per - year, not 60. Option B is wrong because the calculation is about net new residents moving in, not out. Option D is wrong because the expression calculates the net result (new residents in after considering some moving out), not a sequential move - in and move - out of 60 residents.

Answer:

C. After five years, there are 60 new residents in a suburb.