An epidemiologic study examined the incidence of symptomatic Chlamydia infection in a cohort of 2000 young women in a county in Georgia over 5 years. All subjects were enrolled on the same day (Jan 1, 2015), and did not have Chlamydia infection at the time of study enrollment. During the study period, 440 subjects were newly diagnosed with Chlamydia infection. Subjects were followed for a total of 6200 person-years. If no one dropped out of the study and no one developed Chlamydia infection during the study period, how many person-years would be contributed in total by subjects in this study?

step-by-step explanation:

equation

you are asked to write the equation

  expression = 0

using the given expression. when you do that, you have

  2x^2-2x-12 = 0

factoring

you can see that each of the coefficients is even, so a factor of 2 can be removed immediately.

  2(x^2 -x -6) = 0

if you multiply the binomials (x+a)(x+b), you get

  (x +a)(x +b) = x^2 +(a+b)x +ab

this tells you the coefficient of x is the sum of two factors of the constant term. here, that means -1 is the sum of two factors of -6. we want to know those factors so we can factor the trinomial.

  -6 = -1×6 = -2×3 = -3×2 = -6×1

the factor pair that sums to -1 is {-3, 2}, so our factorization is

  2(x -3)(x +2) = 0

solutions

the solutions to this equation are the values of x that make the product zero. a product is zero only when only of the factors of the product is zero. here, that means

  x - 3 = 0

  x = 3 . . . add 3 to both sides of the equation

or

  x +2 = 0

  x = -2 . . . add -2 to both sides of the equation

the solutions to the equation are x=3 or x=-2. both of these values of x satisfy the equation—they make it be true.

the equation cos(35) =a/25 can be used to find the length of bc what is the length of bc? round to the nearest tenth

step-by-step explanation:

25.3

step-by-step explanation:

1st step

add 3+6

=9

multipy 9*3

=37

-1

step-by-step explanation: