When an adult is randomly selected, there is an 85% chance that this person knows what twitter is. find the probability that exactly three out of any five randomly selected adults know of twitter.

b

Step-by-step explanation:x-intercepts:

factor the function

f(x)=(x+3)(x+1)

zeros at x=-3,-1

x-intercepts  --> (-3,0),(-1,0)

y-intercepts:

set x=0 in f(x)

f(0)=(0)^2+4(0)+3=3

y-intercept  --> (0,3)

find minimums and maximums

The max or min of a quadratic function occurs at x=-b/(2a). If a is negative, the max value of the function is f(-b/(2a)).  if a is positive, the minimum value of the function is f(-b/(2a)).

f(x)=ax^2+bx+c

f(x)=x^2+4x+3

here a is positive so you are looking for a minimum,

x=-b/(2a)

x=-4/(2*1)

x=-2   > plug into f(x), f(-2)=(-2)^2+4(-2)+3=-1

minimum (-2,-1)