A, since n=20 and p=5% if children are vaccinated mean number of new infections =np= 20*0.05=1 p(x<=2) = P(x=0)+P(x=1)
y = cost = $25
25 = 0.75 +10
subtract 10 from each side
15=0.75x
x = 15/0.75 = 20
there were 20 words in the ad
Answer:
y=7/3x²-13/3x+2
Step-by-step explanation:
<u>Determine the value of c:</u>
y=ax²+bx+c
2=a(0)²+b(0)+c
2=c
<u>Substitute (1,0) into the quadratic and create an equation with a and b:</u>
y=ax²+bx+2
0=a(1)²+b(1)+2
0=a+b+2
-2=a+b
<u>Do the same with (3,10) to get a second equation:</u>
y=ax²+bx+2
10=a(3)²+b(3)+2
10=9a+3b+2
8=9a+3b
<u>Set the two equations equal to each other and solve for a and b:</u>
-2=a+b
8=9a+3b
<u>Multiply first equation by 3 and eliminate b to find a:</u>
-6=3a+3b
- (8=9a+3b)
_______
-14=-6a
14/6=a
7/3=a
<u>Substitute 7/3=a into the first equation:</u>
-2=7/3+b
-2-(7/3)=b
-13/3=b
<u>Final equation:</u>
y=7/3x²-13/3x+2
See the graph for a visual representation