Question 596129
f(x)=-0.2x^2+12x+11
since f(x) represents the number of tickets sold
to find the last day tickets were sold, set f(x) to zero and solve for x:
f(x)=-0.2x^2+12x+11
0=-0.2x^2+12x+11
0=0.2x^2-12x-11
applying the quadratic formula, we get:
x = {60.9, -0.9}
we can toss out the negative solution (extraneous) leaving:
x = 60 days
.
details of quadratic follows:
*[invoke quadratic "x", .2, -12, -11 ]