Question

The expression 8x2 − 144x + 864 is used to approximate a small town's population in thousands from 1998 to 2018, where x represents the number of years since 1998. Choose the equivalent expression that is most useful for finding the year when the population was at a minimum.

8(x2 − 18x + 108)
8(x2 − 18x) + 108
8(x − 9)2 − 216
8(x − 9)2 + 216

Answer 1

8(x−9)^2 +216

Explanation:

8(x^2 −18x+108)=8((x−9) 2 −9^2 +108)=8((x−9)^2 −81+108).