The function w(x) = -0.01x² + 0.27x + 8.60 can be used to estimate the number of self-employed workers in America in millions, x years after 1980. For what years were there (or will be there) 9.7 million self-employed worker in America?

Answer 1

just solve

-0.01x^2 + 0.27x + 8.60 = 9.7
-0.01x^2 + 0.27x - 1.1 = 0
-0.01(x^2-27x+110) = 0
-0.01(x-5)(x-22) = 0