The city manager made a scatter plot of the number of retail stores in a

city over many years. The trend line for the scatter plot has the equation y =

11x + 12, where y is the total number of stores and x is the number of years

after 1990. Predict how many retail stores there were in 1997.

There were 89 retail stores in 1997.

Step-by-step explanation:

You know:

y = 11*x + 12

where y is the total number of stores and x is the number of years after 1990.

Being this a linear function (Linear functions are those functions that have the form y = mx + b as it happens in this case), to know the total number of stores and, then you must know the value of x, that is, the number of years after 1990, and replace that value in the given function.

To find out how many retail stores there were in 1997, then since 1990 7 years have passed, calculated by subtracting: 1997 - 1990 = 7

So, 7 is the number of years after 1990, then x=7

Replacing in the function y=11*x + 12 you get:

y=11*7+12

Solving:

y=77+12

y=89

There were 89 retail stores in 1997.